src/dhcpv6.c

   1 /**
   2  * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License v2 as published by
   6  * the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  */
  14
  15 #include <time.h>
  16 #include <fcntl.h>
  17 #include <errno.h>
  18 #include <stdlib.h>
  19 #include <signal.h>
  20 #include <limits.h>
  21 #include <resolv.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24 #include <syslog.h>
  25 #include <stdbool.h>
  26 #include <sys/time.h>
  27 #include <sys/ioctl.h>
  28 #include <sys/socket.h>
  29 #include <netinet/in.h>
  30
  31 #include <net/if.h>
  32 #include <net/ethernet.h>
  33
  34 #include "odhcp6c.h"
  35 #include "md5.h"
  36
  37
  38 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
  39                 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
  40 #define DHCPV6_CLIENT_PORT 546
  41 #define DHCPV6_SERVER_PORT 547
  42 #define DHCPV6_DUID_LLADDR 3
  43 #define DHCPV6_REQ_DELAY 1
  44
  45 #define DHCPV6_SOL_MAX_RT_MIN 60
  46 #define DHCPV6_SOL_MAX_RT_MAX 86400
  47 #define DHCPV6_INF_MAX_RT_MIN 60
  48 #define DHCPV6_INF_MAX_RT_MAX 86400
  49
  50 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
  51                 const uint8_t transaction[3], enum dhcpv6_msg type,
  52                 const struct in6_addr *daddr);
  53
  54 static int dhcpv6_parse_ia(void *opt, void *end);
  55
  56 static int dhcpv6_calc_refresh_timers(void);
  57 static void dhcpv6_handle_status_code(_unused const enum dhcpv6_msg orig,
  58                 const uint16_t code, const void *status_msg, const int len,
  59                 int *ret);
  60 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
  61                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
  62                 const void *status_msg, const int len,
  63                 bool handled_status_codes[_DHCPV6_Status_Max],
  64                 int *ret);
  65 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand);
  66 static void dhcpv6_clear_all_server_cand(void);
  67
  68 static reply_handler dhcpv6_handle_reply;
  69 static reply_handler dhcpv6_handle_advert;
  70 static reply_handler dhcpv6_handle_rebind_reply;
  71 static reply_handler dhcpv6_handle_reconfigure;
  72 static int dhcpv6_commit_advert(void);
  73
  74
  75
  76 // RFC 3315 - 5.5 Timeout and Delay values
  77 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
  78         [DHCPV6_MSG_UNKNOWN] = {false, 1, 120, 0, "<POLL>",
  79                         dhcpv6_handle_reconfigure, NULL},
  80         [DHCPV6_MSG_SOLICIT] = {true, 1, DHCPV6_SOL_MAX_RT, 0, "SOLICIT",
  81                         dhcpv6_handle_advert, dhcpv6_commit_advert},
  82         [DHCPV6_MSG_REQUEST] = {true, 1, DHCPV6_REQ_MAX_RT, 10, "REQUEST",
  83                         dhcpv6_handle_reply, NULL},
  84         [DHCPV6_MSG_RENEW] = {false, 10, DHCPV6_REN_MAX_RT, 0, "RENEW",
  85                         dhcpv6_handle_reply, NULL},
  86         [DHCPV6_MSG_REBIND] = {false, 10, DHCPV6_REB_MAX_RT, 0, "REBIND",
  87                         dhcpv6_handle_rebind_reply, NULL},
  88         [DHCPV6_MSG_RELEASE] = {false, 1, 0, 5, "RELEASE", NULL, NULL},
  89         [DHCPV6_MSG_DECLINE] = {false, 1, 0, 5, "DECLINE", NULL, NULL},
  90         [DHCPV6_MSG_INFO_REQ] = {true, 1, DHCPV6_INF_MAX_RT, 0, "INFOREQ",
  91                         dhcpv6_handle_reply, NULL},
  92 };
  93
  94
  95 // Sockets
  96 static int sock = -1;
  97 static int ifindex = -1;
  98 static int64_t t1 = 0, t2 = 0, t3 = 0;
  99
 100 // IA states
 101 static int request_prefix = -1;
 102 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE;
 103 static bool accept_reconfig = false;
 104
 105 // Reconfigure key
 106 static uint8_t reconf_key[16];
 107
 108 // client options
 109 static unsigned int client_options = 0;
 110
 111
 112 int init_dhcpv6(const char *ifname, unsigned int options, int sol_timeout)
 113 {
 114         client_options = options;
 115         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
 116
 117         sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
 118         if (sock < 0)
 119                 return -1;
 120
 121         // Detect interface
 122         struct ifreq ifr;
 123         strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
 124         if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
 125                 return -1;
 126         ifindex = ifr.ifr_ifindex;
 127
 128         // Create client DUID
 129         size_t client_id_len;
 130         odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 131         if (client_id_len == 0) {
 132                 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
 133                                 DHCPV6_DUID_LLADDR, 0, 1};
 134
 135                 if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
 136                         memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
 137
 138                 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
 139                 struct ifreq ifs[100], *ifp, *ifend;
 140                 struct ifconf ifc;
 141                 ifc.ifc_req = ifs;
 142                 ifc.ifc_len = sizeof(ifs);
 143
 144                 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
 145                                 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
 146                         // If our interface doesn't have an address...
 147                         ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
 148                         for (ifp = ifc.ifc_req; ifp < ifend &&
 149                                         !memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
 150                                 memcpy(ifr.ifr_name, ifp->ifr_name,
 151                                                 sizeof(ifr.ifr_name));
 152                                 if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
 153                                         continue;
 154
 155                                 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
 156                                                 ETHER_ADDR_LEN);
 157                         }
 158                 }
 159
 160                 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
 161         }
 162
 163         // Create ORO
 164         if (!(client_options & DHCPV6_STRICT_OPTIONS)) {
 165                 uint16_t oro[] = {
 166                         htons(DHCPV6_OPT_SIP_SERVER_D),
 167                         htons(DHCPV6_OPT_SIP_SERVER_A),
 168                         htons(DHCPV6_OPT_DNS_SERVERS),
 169                         htons(DHCPV6_OPT_DNS_DOMAIN),
 170                         htons(DHCPV6_OPT_SNTP_SERVERS),
 171                         htons(DHCPV6_OPT_NTP_SERVER),
 172                         htons(DHCPV6_OPT_AFTR_NAME),
 173                         htons(DHCPV6_OPT_PD_EXCLUDE),
 174                         htons(DHCPV6_OPT_SOL_MAX_RT),
 175                         htons(DHCPV6_OPT_INF_MAX_RT),
 176 #ifdef EXT_PREFIX_CLASS
 177                         htons(DHCPV6_OPT_PREFIX_CLASS),
 178 #endif
 179 #ifdef EXT_CER_ID
 180                         htons(DHCPV6_OPT_CER_ID),
 181 #endif
 182                         htons(DHCPV6_OPT_S46_CONT_MAPE),
 183                         htons(DHCPV6_OPT_S46_CONT_MAPT),
 184                         htons(DHCPV6_OPT_S46_CONT_LW),
 185                 };
 186                 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
 187         }
 188
 189         // Configure IPv6-options
 190         int val = 1;
 191         setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
 192         setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
 193         setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
 194         setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
 195
 196         struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
 197                 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
 198         if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
 199                 return -1;
 200
 201         return 0;
 202 }
 203
 204 enum {
 205         IOV_HDR=0,
 206         IOV_ORO,
 207         IOV_ORO_REFRESH,
 208         IOV_CL_ID,
 209         IOV_SRV_ID,
 210         IOV_VENDOR_CLASS_HDR,
 211         IOV_VENDOR_CLASS,
 212         IOV_USER_CLASS_HDR,
 213         IOV_USER_CLASS,
 214         IOV_RECONF_ACCEPT,
 215         IOV_FQDN,
 216         IOV_HDR_IA_NA,
 217         IOV_IA_NA,
 218         IOV_IA_PD,
 219         IOV_TOTAL
 220 };
 221
 222 void dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
 223 {
 224         na_mode = na;
 225         pd_mode = pd;
 226 }
 227
 228 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
 229 {
 230         // Build FQDN
 231         char fqdn_buf[256];
 232         gethostname(fqdn_buf, sizeof(fqdn_buf));
 233         struct {
 234                 uint16_t type;
 235                 uint16_t len;
 236                 uint8_t flags;
 237                 uint8_t data[256];
 238         } fqdn;
 239         size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
 240                         sizeof(fqdn.data), NULL, NULL);
 241         fqdn.type = htons(DHCPV6_OPT_FQDN);
 242         fqdn.len = htons(fqdn_len - 4);
 243         fqdn.flags = 0;
 244
 245
 246         // Build Client ID
 247         size_t cl_id_len;
 248         void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
 249
 250         // Get Server ID
 251         size_t srv_id_len;
 252         void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
 253
 254         // Build IA_PDs
 255         size_t ia_pd_entries = 0, ia_pd_len = 0;
 256         uint8_t *ia_pd;
 257
 258         if (type == DHCPV6_MSG_SOLICIT) {
 259                 odhcp6c_clear_state(STATE_IA_PD);
 260                 size_t n_prefixes;
 261                 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
 262                 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
 263
 264                 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
 265
 266                 for (size_t i = 0; i < n_prefixes; i++) {
 267                         struct dhcpv6_ia_hdr hdr_ia_pd = {
 268                                 htons(DHCPV6_OPT_IA_PD),
 269                                 htons(sizeof(hdr_ia_pd) - 4 + sizeof(struct dhcpv6_ia_prefix)),
 270                                 request_prefixes[i].iaid, 0, 0
 271                         };
 272                         struct dhcpv6_ia_prefix pref = {
 273                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 274                                 .len = htons(25), .prefix = request_prefixes[i].length
 275                         };
 276                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
 277                         ia_pd_len += sizeof(hdr_ia_pd);
 278                         memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
 279                         ia_pd_len += sizeof(pref);
 280                 }
 281         } else {
 282                 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
 283                 ia_pd_entries /= sizeof(*e);
 284
 285                 // we're too lazy to count our distinct IAIDs,
 286                 // so just allocate maximally needed space
 287                 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
 288                                         sizeof(struct dhcpv6_ia_hdr)));
 289
 290                 for (size_t i = 0; i < ia_pd_entries; ++i) {
 291                         uint32_t iaid = e[i].iaid;
 292
 293                         // check if this is an unprocessed IAID and skip if not.
 294                         int new_iaid = 1;
 295                         for (int j = i-1; j >= 0; j--) {
 296                                 if (e[j].iaid == iaid) {
 297                                         new_iaid = 0;
 298                                         break;
 299                                 }
 300                         }
 301
 302                         if (!new_iaid)
 303                                 continue;
 304
 305                         // construct header
 306                         struct dhcpv6_ia_hdr hdr_ia_pd = {
 307                                 htons(DHCPV6_OPT_IA_PD),
 308                                 htons(sizeof(hdr_ia_pd) - 4),
 309                                 iaid, 0, 0
 310                         };
 311
 312                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
 313                         struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
 314                         ia_pd_len += sizeof(hdr_ia_pd);
 315
 316                         for (size_t j = i; j < ia_pd_entries; j++) {
 317                                 if (e[j].iaid != iaid)
 318                                         continue;
 319
 320                                 uint8_t ex_len = 0;
 321                                 if (e[j].priority > 0)
 322                                         ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
 323
 324                                 struct dhcpv6_ia_prefix p = {
 325                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 326                                         .len = htons(sizeof(p) - 4U + ex_len),
 327                                         .prefix = e[j].length,
 328                                         .addr = e[j].target
 329                                 };
 330
 331                                 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
 332                                 ia_pd_len += sizeof(p);
 333
 334                                 if (ex_len) {
 335                                         ia_pd[ia_pd_len++] = 0;
 336                                         ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
 337                                         ia_pd[ia_pd_len++] = 0;
 338                                         ia_pd[ia_pd_len++] = ex_len - 4;
 339                                         ia_pd[ia_pd_len++] = e[j].priority;
 340
 341                                         uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
 342                                         excl >>= (64 - e[j].priority);
 343                                         excl <<= 8 - ((e[j].priority - e[j].length) % 8);
 344
 345                                         for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
 346                                                 ia_pd[ia_pd_len + i] = excl & 0xff;
 347                                         ia_pd_len += ex_len - 5;
 348                                 }
 349
 350                                 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
 351                         }
 352                 }
 353         }
 354
 355         if (ia_pd_entries > 0)
 356                 request_prefix = 1;
 357
 358         // Build IA_NAs
 359         size_t ia_na_entries, ia_na_len = 0;
 360         void *ia_na = NULL;
 361         struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
 362         ia_na_entries /= sizeof(*e);
 363
 364         struct dhcpv6_ia_hdr hdr_ia_na = {
 365                 htons(DHCPV6_OPT_IA_NA),
 366                 htons(sizeof(hdr_ia_na) - 4),
 367                 htonl(1), 0, 0
 368         };
 369
 370         struct dhcpv6_ia_addr pa[ia_na_entries];
 371         for (size_t i = 0; i < ia_na_entries; ++i) {
 372                 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
 373                 pa[i].len = htons(sizeof(pa[i]) - 4U);
 374                 pa[i].addr = e[i].target;
 375                 pa[i].preferred = 0;
 376                 pa[i].valid = 0;
 377         }
 378
 379         ia_na = pa;
 380         ia_na_len = sizeof(pa);
 381         hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
 382
 383         // Reconfigure Accept
 384         struct {
 385                 uint16_t type;
 386                 uint16_t length;
 387         } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
 388
 389         // Request Information Refresh
 390         uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
 391
 392         // Build vendor-class option
 393         size_t vendor_class_len, user_class_len;
 394         struct dhcpv6_vendorclass *vendor_class = odhcp6c_get_state(STATE_VENDORCLASS, &vendor_class_len);
 395         void *user_class = odhcp6c_get_state(STATE_USERCLASS, &user_class_len);
 396
 397         struct {
 398                 uint16_t type;
 399                 uint16_t length;
 400         } vendor_class_hdr = {htons(DHCPV6_OPT_VENDOR_CLASS), htons(vendor_class_len)};
 401
 402         struct {
 403                 uint16_t type;
 404                 uint16_t length;
 405         } user_class_hdr = {htons(DHCPV6_OPT_USER_CLASS), htons(user_class_len)};
 406
 407         // Prepare Header
 408         size_t oro_len;
 409         void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
 410         struct {
 411                 uint8_t type;
 412                 uint8_t trid[3];
 413                 uint16_t elapsed_type;
 414                 uint16_t elapsed_len;
 415                 uint16_t elapsed_value;
 416                 uint16_t oro_type;
 417                 uint16_t oro_len;
 418         } hdr = {
 419                 type, {trid[0], trid[1], trid[2]},
 420                 htons(DHCPV6_OPT_ELAPSED), htons(2),
 421                         htons((ecs > 0xffff) ? 0xffff : ecs),
 422                 htons(DHCPV6_OPT_ORO), htons(oro_len),
 423         };
 424
 425         struct iovec iov[IOV_TOTAL] = {
 426                 [IOV_HDR] = {&hdr, sizeof(hdr)},
 427                 [IOV_ORO] = {oro, oro_len},
 428                 [IOV_ORO_REFRESH] = {&oro_refresh, 0},
 429                 [IOV_CL_ID] = {cl_id, cl_id_len},
 430                 [IOV_SRV_ID] = {srv_id, srv_id_len},
 431                 [IOV_VENDOR_CLASS_HDR] = {&vendor_class_hdr, vendor_class_len ? sizeof(vendor_class_hdr) : 0},
 432                 [IOV_VENDOR_CLASS] = {vendor_class, vendor_class_len},
 433                 [IOV_USER_CLASS_HDR] = {&user_class_hdr, user_class_len ? sizeof(user_class_hdr) : 0},
 434                 [IOV_USER_CLASS] = {user_class, user_class_len},
 435                 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
 436                 [IOV_FQDN] = {&fqdn, fqdn_len},
 437                 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
 438                 [IOV_IA_NA] = {ia_na, ia_na_len},
 439                 [IOV_IA_PD] = {ia_pd, ia_pd_len},
 440         };
 441
 442         size_t cnt = IOV_TOTAL;
 443         if (type == DHCPV6_MSG_INFO_REQ) {
 444                 cnt = 9;
 445                 iov[IOV_ORO_REFRESH].iov_len = sizeof(oro_refresh);
 446                 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
 447         } else if (!request_prefix) {
 448                 cnt = 13;
 449         }
 450
 451         // Disable IAs if not used
 452         if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
 453                 iov[IOV_HDR_IA_NA].iov_len = 0;
 454
 455         if (na_mode == IA_MODE_NONE)
 456                 iov[IOV_HDR_IA_NA].iov_len = 0;
 457
 458         if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
 459                         !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
 460                 iov[IOV_RECONF_ACCEPT].iov_len = 0;
 461
 462         if (!(client_options & DHCPV6_CLIENT_FQDN))
 463                 iov[IOV_FQDN].iov_len = 0;
 464
 465         struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
 466                 0, ALL_DHCPV6_RELAYS, ifindex};
 467         struct msghdr msg = {&srv, sizeof(srv), iov, cnt, NULL, 0, 0};
 468
 469         sendmsg(sock, &msg, 0);
 470 }
 471
 472
 473 static int64_t dhcpv6_rand_delay(int64_t time)
 474 {
 475         int random;
 476         odhcp6c_random(&random, sizeof(random));
 477         return (time * ((int64_t)random % 1000LL)) / 10000LL;
 478 }
 479
 480
 481 int dhcpv6_request(enum dhcpv6_msg type)
 482 {
 483         uint8_t rc = 0;
 484         uint64_t timeout = UINT32_MAX;
 485         struct dhcpv6_retx *retx = &dhcpv6_retx[type];
 486
 487         if (retx->delay) {
 488                 struct timespec ts = {0, 0};
 489                 ts.tv_nsec = dhcpv6_rand_delay(10 * DHCPV6_REQ_DELAY);
 490                 nanosleep(&ts, NULL);
 491         }
 492
 493         if (type == DHCPV6_MSG_UNKNOWN)
 494                 timeout = t1;
 495         else if (type == DHCPV6_MSG_RENEW)
 496                 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
 497         else if (type == DHCPV6_MSG_REBIND)
 498                 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
 499
 500         if (timeout == 0)
 501                 return -1;
 502
 503         syslog(LOG_NOTICE, "Starting %s transaction (timeout %llus, max rc %d)",
 504                         retx->name, (unsigned long long)timeout, retx->max_rc);
 505
 506         uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
 507
 508         // Generate transaction ID
 509         uint8_t trid[3] = {0, 0, 0};
 510         if (type != DHCPV6_MSG_UNKNOWN)
 511                 odhcp6c_random(trid, sizeof(trid));
 512         ssize_t len = -1;
 513         int64_t rto = 0;
 514
 515         do {
 516                 if (rto == 0) {
 517                         int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 518
 519                         // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
 520                         while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
 521                                 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 522
 523                         rto = (retx->init_timeo * 1000 + delay);
 524                 }
 525                 else
 526                         rto = (2 * rto + dhcpv6_rand_delay(rto));
 527
 528                 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
 529                         rto = retx->max_timeo * 1000 +
 530                                 dhcpv6_rand_delay(retx->max_timeo * 1000);
 531
 532                 // Calculate end for this round and elapsed time
 533                 uint64_t round_end = round_start + rto;
 534                 elapsed = round_start - start;
 535
 536                 // Don't wait too long if timeout differs from infinite
 537                 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
 538                         round_end = timeout * 1000 + start;
 539
 540                 // Built and send package
 541                 if (type != DHCPV6_MSG_UNKNOWN) {
 542                         if (type != DHCPV6_MSG_SOLICIT)
 543                                 syslog(LOG_NOTICE, "Send %s message (elapsed %llums, rc %d)",
 544                                                 retx->name, (unsigned long long)elapsed, rc);
 545                         dhcpv6_send(type, trid, elapsed / 10);
 546                         rc++;
 547                 }
 548
 549                 // Receive rounds
 550                 for (; len < 0 && (round_start < round_end);
 551                                 round_start = odhcp6c_get_milli_time()) {
 552                         uint8_t buf[1536], cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
 553                         struct iovec iov = {buf, sizeof(buf)};
 554                         struct sockaddr_in6 addr;
 555                         struct msghdr msg = {&addr, sizeof(addr), &iov, 1,
 556                                         cmsg_buf, sizeof(cmsg_buf), 0};
 557                         struct in6_pktinfo *pktinfo = NULL;
 558
 559
 560                         // Check for pending signal
 561                         if (odhcp6c_signal_process())
 562                                 return -1;
 563
 564                         // Set timeout for receiving
 565                         uint64_t t = round_end - round_start;
 566                         struct timeval tv = {t / 1000, (t % 1000) * 1000};
 567                         setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
 568                                         &tv, sizeof(tv));
 569
 570                         // Receive cycle
 571                         len = recvmsg(sock, &msg, 0);
 572                         if (len < 0)
 573                                 continue;
 574
 575                         for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
 576                                 ch = CMSG_NXTHDR(&msg, ch)) {
 577                                 if (ch->cmsg_level == SOL_IPV6 &&
 578                                         ch->cmsg_type == IPV6_PKTINFO) {
 579                                         pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
 580                                         break;
 581                                 }
 582                         }
 583
 584                         if (pktinfo == NULL) {
 585                                 len = -1;
 586                                 continue;
 587                         }
 588
 589                         if (!dhcpv6_response_is_valid(buf, len, trid,
 590                                                         type, &pktinfo->ipi6_addr)) {
 591                                 len = -1;
 592                                 continue;
 593                         }
 594
 595                         uint8_t *opt = &buf[4];
 596                         uint8_t *opt_end = opt + len - 4;
 597
 598                         round_start = odhcp6c_get_milli_time();
 599                         elapsed = round_start - start;
 600                         syslog(LOG_NOTICE, "Got a valid reply after "
 601                                         "%llums", (unsigned long long)elapsed);
 602
 603                         if (retx->handler_reply)
 604                                 len = retx->handler_reply(type, rc, opt, opt_end, &addr);
 605
 606                         if (len > 0 && round_end - round_start > 1000)
 607                                 round_end = 1000 + round_start;
 608                 }
 609
 610                 // Allow
 611                 if (retx->handler_finish)
 612                         len = retx->handler_finish();
 613         } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
 614                         (!retx->max_rc || rc < retx->max_rc));
 615         return len;
 616 }
 617
 618 // Message validation checks according to RFC3315 chapter 15
 619 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
 620                 const uint8_t transaction[3], enum dhcpv6_msg type,
 621                 const struct in6_addr *daddr)
 622 {
 623         const struct dhcpv6_header *rep = buf;
 624         if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
 625                         transaction, sizeof(rep->tr_id)))
 626                 return false; // Invalid reply
 627
 628         if (type == DHCPV6_MSG_SOLICIT) {
 629                 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
 630                                 rep->msg_type != DHCPV6_MSG_REPLY)
 631                         return false;
 632         } else if (type == DHCPV6_MSG_UNKNOWN) {
 633                 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
 634                         return false;
 635         } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
 636                 return false;
 637         }
 638
 639         uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
 640                 rcmsg = DHCPV6_MSG_UNKNOWN;
 641         uint16_t otype, olen = UINT16_MAX;
 642         bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
 643                 ia_present = false, options_valid = true;
 644
 645         size_t client_id_len, server_id_len;
 646         void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 647         void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 648
 649         dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
 650                 if (otype == DHCPV6_OPT_CLIENTID) {
 651                         clientid_ok = (olen + 4U == client_id_len) && !memcmp(
 652                                         &odata[-4], client_id, client_id_len);
 653                 } else if (otype == DHCPV6_OPT_SERVERID) {
 654                         if (server_id_len)
 655                                 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
 656                                                 &odata[-4], server_id, server_id_len);
 657                         else
 658                                 serverid_ok = true;
 659                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
 660                                 sizeof(struct dhcpv6_auth_reconfigure)) {
 661                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
 662                         if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
 663                                 continue;
 664
 665                         md5_ctx_t md5;
 666                         uint8_t serverhash[16], secretbytes[64], hash[16];
 667                         memcpy(serverhash, r->key, sizeof(serverhash));
 668                         memset(r->key, 0, sizeof(r->key));
 669
 670                         memset(secretbytes, 0, sizeof(secretbytes));
 671                         memcpy(secretbytes, reconf_key, sizeof(reconf_key));
 672
 673                         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 674                                 secretbytes[i] ^= 0x36;
 675
 676                         md5_begin(&md5);
 677                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 678                         md5_hash(buf, len, &md5);
 679                         md5_end(hash, &md5);
 680
 681                         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 682                                 secretbytes[i] ^= 0x36;
 683                                 secretbytes[i] ^= 0x5c;
 684                         }
 685
 686                         md5_begin(&md5);
 687                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 688                         md5_hash(hash, 16, &md5);
 689                         md5_end(hash, &md5);
 690
 691                         rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
 692                 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
 693                         rcmsg = odata[0];
 694                 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
 695                         ia_present = true;
 696                         if (olen < sizeof(struct dhcpv6_ia_hdr))
 697                                 options_valid = false;
 698                 }
 699                 else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
 700                                 (otype == DHCPV6_OPT_PD_EXCLUDE)) {
 701                         // Options are not allowed on global level
 702                         options_valid = false;
 703                 }
 704         }
 705
 706         if (!options_valid || ((odata + olen) > end))
 707                 return false;
 708
 709         if (type == DHCPV6_MSG_INFO_REQ && ia_present)
 710                 return false;
 711
 712         if (rep->msg_type == DHCPV6_MSG_RECONF) {
 713                 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
 714                         (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
 715                         !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
 716                         return false;
 717         }
 718
 719         return clientid_ok && serverid_ok;
 720 }
 721
 722
 723 int dhcpv6_poll_reconfigure(void)
 724 {
 725         int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
 726         if (ret != -1)
 727                 ret = dhcpv6_request(ret);
 728
 729         return ret;
 730 }
 731
 732
 733 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
 734                 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
 735 {
 736         uint16_t otype, olen;
 737         uint8_t *odata, msg = DHCPV6_MSG_RENEW;
 738         dhcpv6_for_each_option(opt, end, otype, olen, odata)
 739                 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
 740                                 odata[0] == DHCPV6_MSG_RENEW ||
 741                                 odata[0] == DHCPV6_MSG_INFO_REQ))
 742                         msg = odata[0];
 743
 744         dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL, NULL);
 745         return msg;
 746 }
 747
 748
 749 // Collect all advertised servers
 750 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
 751                 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
 752 {
 753         uint16_t olen, otype;
 754         uint8_t *odata, pref = 0;
 755         struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
 756                                         DHCPV6_SOL_MAX_RT,
 757                                         DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
 758         bool have_na = false;
 759         int have_pd = 0;
 760
 761         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 762                 if (orig == DHCPV6_MSG_SOLICIT &&
 763                                 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
 764                                 olen > sizeof(struct dhcpv6_ia_hdr)) {
 765                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 766                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 767                 }
 768
 769                 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
 770                         memcpy(cand.duid, odata, olen);
 771                         cand.duid_len = olen;
 772                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
 773                         int error = ((int)odata[0] << 8 | (int)odata[1]);
 774
 775                         switch (error) {
 776                         case DHCPV6_NoPrefixAvail:
 777                                 // Status code on global level
 778                                 cand.preference -= 2000;
 779                                 break;
 780
 781                         default :
 782                                 break;
 783                         }
 784                 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
 785                                 cand.preference >= 0) {
 786                         cand.preference = pref = odata[0];
 787                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 788                         cand.wants_reconfigure = true;
 789                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
 790                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
 791                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
 792                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
 793                                 cand.sol_max_rt = sol_max_rt;
 794                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
 795                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
 796                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
 797                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
 798                                 cand.inf_max_rt = inf_max_rt;
 799                 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
 800                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 801                         uint8_t *oend = odata + olen, *d;
 802                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
 803                                 if (otype == DHCPV6_OPT_IA_PREFIX && (olen + 4) >=
 804                                                 (uint16_t)sizeof(struct dhcpv6_ia_prefix)) {
 805                                         struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
 806                                         have_pd = p->prefix;
 807                                 }
 808                         }
 809                 } else if (otype == DHCPV6_OPT_IA_NA) {
 810                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 811                         uint8_t *oend = odata + olen, *d;
 812                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
 813                                 if (otype == DHCPV6_OPT_IA_ADDR)
 814                                         have_na = true;
 815                 }
 816         }
 817
 818         if ((!have_na && na_mode == IA_MODE_FORCE) ||
 819                         (!have_pd && pd_mode == IA_MODE_FORCE)) {
 820                 /*
 821                  * RFC7083 states to process the SOL_MAX_RT and
 822                  * INF_MAX_RT options even if the DHCPv6 server
 823                  * did not propose any IA_NA and/or IA_PD
 824                  */
 825                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
 826                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
 827                 return -1;
 828         }
 829
 830         if (na_mode != IA_MODE_NONE && !have_na) {
 831                 cand.has_noaddravail = true;
 832                 cand.preference -= 1000;
 833         }
 834
 835         if (pd_mode != IA_MODE_NONE) {
 836                 if (have_pd)
 837                         cand.preference += 2000 + (128 - have_pd);
 838                 else
 839                         cand.preference -= 2000;
 840         }
 841
 842         if (cand.duid_len > 0) {
 843                 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
 844                 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
 845                 dhcpv6_add_server_cand(&cand);
 846         }
 847
 848         return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
 849 }
 850
 851
 852 static int dhcpv6_commit_advert(void)
 853 {
 854         return dhcpv6_promote_server_cand();
 855 }
 856
 857
 858 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
 859                 const void *opt, const void *end, const struct sockaddr_in6 *from)
 860 {
 861         dhcpv6_handle_advert(orig, rc, opt, end, from);
 862         if (dhcpv6_commit_advert() < 0)
 863                 return -1;
 864
 865         return dhcpv6_handle_reply(orig, rc, opt, end, from);
 866 }
 867
 868
 869 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
 870                 const void *opt, const void *end, const struct sockaddr_in6 *from)
 871 {
 872         uint8_t *odata;
 873         uint16_t otype, olen;
 874         uint32_t refresh = UINT32_MAX;
 875         int ret = 1;
 876         bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
 877
 878         odhcp6c_expire();
 879
 880         if (orig == DHCPV6_MSG_UNKNOWN) {
 881                 static time_t last_update = 0;
 882                 time_t now = odhcp6c_get_milli_time() / 1000;
 883
 884                 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 885                 last_update = now;
 886
 887                 if (t1 != UINT32_MAX)
 888                         t1 -= elapsed;
 889
 890                 if (t2 != UINT32_MAX)
 891                         t2 -= elapsed;
 892
 893                 if (t3 != UINT32_MAX)
 894                         t3 -= elapsed;
 895
 896                 if (t1 < 0)
 897                         t1 = 0;
 898
 899                 if (t2 < 0)
 900                         t2 = 0;
 901
 902                 if (t3 < 0)
 903                         t3 = 0;
 904         }
 905
 906         if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
 907                 // Delete NA and PD we have in the state from the Advert
 908                 odhcp6c_clear_state(STATE_IA_NA);
 909                 odhcp6c_clear_state(STATE_IA_PD);
 910         }
 911
 912         if (opt) {
 913                 odhcp6c_clear_state(STATE_DNS);
 914                 odhcp6c_clear_state(STATE_SEARCH);
 915                 odhcp6c_clear_state(STATE_SNTP_IP);
 916                 odhcp6c_clear_state(STATE_NTP_IP);
 917                 odhcp6c_clear_state(STATE_NTP_FQDN);
 918                 odhcp6c_clear_state(STATE_SIP_IP);
 919                 odhcp6c_clear_state(STATE_SIP_FQDN);
 920                 odhcp6c_clear_state(STATE_AFTR_NAME);
 921                 odhcp6c_clear_state(STATE_CER);
 922                 odhcp6c_clear_state(STATE_S46_MAPT);
 923                 odhcp6c_clear_state(STATE_S46_MAPE);
 924                 odhcp6c_clear_state(STATE_S46_LW);
 925                 odhcp6c_clear_state(STATE_PASSTHRU);
 926         }
 927
 928         // Parse and find all matching IAs
 929         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 930                 bool passthru = true;
 931
 932                 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
 933                                 && olen > sizeof(struct dhcpv6_ia_hdr)) {
 934                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 935
 936                         // Test ID
 937                         if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
 938                                 continue;
 939
 940                         uint16_t code = DHCPV6_Success;
 941                         uint16_t stype, slen;
 942                         uint8_t *sdata;
 943                         // Get and handle status code
 944                         dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
 945                                         stype, slen, sdata) {
 946                                 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
 947                                         uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
 948                                         uint16_t mlen = (slen > 2) ? slen - 2 : 0;
 949
 950                                         code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
 951
 952                                         if (code == DHCPV6_Success)
 953                                                 continue;
 954
 955                                         dhcpv6_handle_ia_status_code(orig, ia_hdr,
 956                                                 code, mdata, mlen, handled_status_codes, &ret);
 957
 958
 959                                         if (ret > 0)
 960                                                 return ret;
 961                                         break;
 962                                 }
 963                         }
 964
 965                         if (code != DHCPV6_Success)
 966                                 continue;
 967
 968                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 969                         passthru = false;
 970                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
 971                         uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
 972                         uint16_t mlen = (olen > 2) ? olen - 2 : 0;
 973                         uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
 974
 975                         dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
 976                         passthru = false;
 977                 }
 978                 else if (otype == DHCPV6_OPT_DNS_SERVERS) {
 979                         if (olen % 16 == 0)
 980                                 odhcp6c_add_state(STATE_DNS, odata, olen);
 981                 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
 982                         odhcp6c_add_state(STATE_SEARCH, odata, olen);
 983                         passthru = false;
 984                 } else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
 985                         if (olen % 16 == 0)
 986                                 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
 987                 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
 988                         uint16_t stype, slen;
 989                         uint8_t *sdata;
 990                         // Test status and bail if error
 991                         dhcpv6_for_each_option(odata, odata + olen,
 992                                         stype, slen, sdata) {
 993                                 if (slen == 16 && (stype == NTP_MC_ADDR ||
 994                                                 stype == NTP_SRV_ADDR))
 995                                         odhcp6c_add_state(STATE_NTP_IP,
 996                                                         sdata, slen);
 997                                 else if (slen > 0 && stype == NTP_SRV_FQDN)
 998                                         odhcp6c_add_state(STATE_NTP_FQDN,
 999                                                         sdata, slen);
1000                         }
1001                 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1002                         if (olen == 16)
1003                                 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1004                 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
1005                         odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1006                 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1007                         refresh = ntohl(*((uint32_t*)odata));
1008                         passthru = false;
1009                 } else if (otype == DHCPV6_OPT_AUTH) {
1010                         if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1011                                 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1012                                 if (r->protocol == 3 && r->algorithm == 1 &&
1013                                                 r->reconf_type == 1)
1014                                         memcpy(reconf_key, r->key, sizeof(r->key));
1015                         }
1016                         passthru = false;
1017                 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1018                         size_t cur_len;
1019                         odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1020                         if (cur_len == 0)
1021                                 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1022                         passthru = false;
1023                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1024                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
1025                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1026                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1027                                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1028                         passthru = false;
1029                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1030                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
1031                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1032                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1033                                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1034                         passthru = false;
1035 #ifdef EXT_CER_ID
1036                 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1037                                 sizeof(struct dhcpv6_cer_id)) {
1038                         struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1039                         struct in6_addr any = IN6ADDR_ANY_INIT;
1040                         if (memcmp(&cer_id->addr, &any, sizeof(any)))
1041                                 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1042                         passthru = false;
1043 #endif
1044                 } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1045                         odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1046                         passthru = false;
1047                 } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1048                         size_t mape_len;
1049                         odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1050                         if (mape_len == 0)
1051                                 odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1052                         passthru = false;
1053                 } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1054                         odhcp6c_add_state(STATE_S46_LW, odata, olen);
1055                         passthru = false;
1056                 } else if (otype == DHCPV6_OPT_CLIENTID ||
1057                                 otype == DHCPV6_OPT_SERVERID ||
1058                                 otype == DHCPV6_OPT_IA_TA ||
1059                                 otype == DHCPV6_OPT_PREF ||
1060                                 otype == DHCPV6_OPT_UNICAST ||
1061                                 otype == DHCPV6_OPT_FQDN ||
1062                                 otype == DHCPV6_OPT_RECONF_ACCEPT) {
1063                         passthru = false;
1064                 } else {
1065                         odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1066                 }
1067
1068                 if (passthru)
1069                         odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1070         }
1071
1072         if (orig != DHCPV6_MSG_INFO_REQ) {
1073                 // Update refresh timers if no fatal status code was received
1074                 if ((ret > 0) && dhcpv6_calc_refresh_timers()) {
1075                         switch (orig) {
1076                         case DHCPV6_MSG_RENEW:
1077                                 // Send further renews if T1 is not set
1078                                 if (!t1)
1079                                         ret = -1;
1080                                 break;
1081                         case DHCPV6_MSG_REBIND:
1082                                 // Send further rebinds if T1 and T2 is not set
1083                                 if (!t1 && !t2)
1084                                         ret = -1;
1085                                 break;
1086
1087                         case DHCPV6_MSG_REQUEST:
1088                                 // All server candidates can be cleared if not yet bound
1089                                 if (!odhcp6c_is_bound())
1090                                         dhcpv6_clear_all_server_cand();
1091
1092                         default :
1093                                 break;
1094                         }
1095
1096                         if (orig == DHCPV6_MSG_REBIND || orig == DHCPV6_MSG_REQUEST) {
1097                                 odhcp6c_clear_state(STATE_SERVER_ADDR);
1098                                 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1099                         }
1100                 }
1101         }
1102         else if (ret > 0) {
1103                 // All server candidates can be cleared if not yet bound
1104                 if (!odhcp6c_is_bound())
1105                         dhcpv6_clear_all_server_cand();
1106
1107                 t1 = refresh;
1108         }
1109
1110         return ret;
1111 }
1112
1113
1114 static int dhcpv6_parse_ia(void *opt, void *end)
1115 {
1116         struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1117         int parsed_ia = 0;
1118         uint32_t t1, t2;
1119         uint16_t otype, olen;
1120         uint8_t *odata;
1121
1122         t1 = ntohl(ia_hdr->t1);
1123         t2 = ntohl(ia_hdr->t2);
1124
1125         if (t1 > t2)
1126                 return 0;
1127
1128         // Update address IA
1129         dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1130                 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
1131                                 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0, 0};
1132
1133                 entry.iaid = ia_hdr->iaid;
1134
1135                 if (otype == DHCPV6_OPT_IA_PREFIX) {
1136                         struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1137                         if (olen + 4U < sizeof(*prefix))
1138                                 continue;
1139
1140                         entry.valid = ntohl(prefix->valid);
1141                         entry.preferred = ntohl(prefix->preferred);
1142
1143                         if (entry.preferred > entry.valid)
1144                                 continue;
1145
1146                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1147                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1148                         if (entry.t1 > entry.t2)
1149                                 entry.t1 = entry.t2;
1150
1151                         entry.length = prefix->prefix;
1152                         entry.target = prefix->addr;
1153                         uint16_t stype, slen;
1154                         uint8_t *sdata;
1155
1156 #ifdef EXT_PREFIX_CLASS
1157                         // Find prefix class, if any
1158                         dhcpv6_for_each_option(&prefix[1], odata + olen,
1159                                         stype, slen, sdata)
1160                                 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1161                                         entry.class = sdata[0] << 8 | sdata[1];
1162 #endif
1163
1164                         // Parse PD-exclude
1165                         bool ok = true;
1166                         dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1167                                         odata + olen, stype, slen, sdata) {
1168                                 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1169                                         continue;
1170
1171                                 uint8_t elen = sdata[0];
1172                                 if (elen > 64)
1173                                         elen = 64;
1174
1175                                 if (elen <= 32 || elen <= entry.length) {
1176                                         ok = false;
1177                                         continue;
1178                                 }
1179
1180
1181                                 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1182                                 if (slen <= bytes) {
1183                                         ok = false;
1184                                         continue;
1185                                 }
1186
1187                                 uint32_t exclude = 0;
1188                                 do {
1189                                         exclude = exclude << 8 | sdata[bytes];
1190                                 } while (--bytes);
1191
1192                                 exclude >>= 8 - ((elen - entry.length) % 8);
1193                                 exclude <<= 64 - elen;
1194
1195                                 // Abusing router & priority fields for exclusion
1196                                 entry.router = entry.target;
1197                                 entry.router.s6_addr32[1] |= htonl(exclude);
1198                                 entry.priority = elen;
1199                         }
1200
1201                         if (ok) {
1202                                 odhcp6c_update_entry(STATE_IA_PD, &entry);
1203                                 parsed_ia++;
1204                         }
1205
1206                         entry.priority = 0;
1207                         memset(&entry.router, 0, sizeof(entry.router));
1208                 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1209                         struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1210                         if (olen + 4U < sizeof(*addr))
1211                                 continue;
1212
1213                         entry.preferred = ntohl(addr->preferred);
1214                         entry.valid = ntohl(addr->valid);
1215
1216                         if (entry.preferred > entry.valid)
1217                                 continue;
1218
1219                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1220                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1221                         if (entry.t1 > entry.t2)
1222                                 entry.t1 = entry.t2;
1223
1224                         entry.length = 128;
1225                         entry.target = addr->addr;
1226
1227 #ifdef EXT_PREFIX_CLASS
1228                         uint16_t stype, slen;
1229                         uint8_t *sdata;
1230                         // Find prefix class, if any
1231                         dhcpv6_for_each_option(&addr[1], odata + olen,
1232                                         stype, slen, sdata)
1233                                 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1234                                         entry.class = sdata[0] << 8 | sdata[1];
1235 #endif
1236
1237                         odhcp6c_update_entry(STATE_IA_NA, &entry);
1238                         parsed_ia++;
1239                 }
1240         }
1241         return parsed_ia;
1242 }
1243
1244
1245 static int dhcpv6_calc_refresh_timers(void)
1246 {
1247         struct odhcp6c_entry *e;
1248         size_t ia_na_entries, ia_pd_entries, i;
1249         int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1250
1251         e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1252         ia_na_entries /= sizeof(*e);
1253         for (i = 0; i < ia_na_entries; i++) {
1254                 if (e[i].t1 < l_t1)
1255                         l_t1 = e[i].t1;
1256
1257                 if (e[i].t2 < l_t2)
1258                         l_t2 = e[i].t2;
1259
1260                 if (e[i].valid > l_t3)
1261                         l_t3 = e[i].valid;
1262         }
1263
1264         e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1265         ia_pd_entries /= sizeof(*e);
1266         for (i = 0; i < ia_pd_entries; i++) {
1267                 if (e[i].t1 < l_t1)
1268                         l_t1 = e[i].t1;
1269
1270                 if (e[i].t2 < l_t2)
1271                         l_t2 = e[i].t2;
1272
1273                 if (e[i].valid > l_t3)
1274                         l_t3 = e[i].valid;
1275         }
1276
1277         if (ia_pd_entries || ia_na_entries) {
1278                 t1 = l_t1;
1279                 t2 = l_t2;
1280                 t3 = l_t3;
1281         } else {
1282                 t1 = 600;
1283         }
1284
1285         return (int)(ia_pd_entries + ia_na_entries);
1286 }
1287
1288
1289 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1290                 const void *status_msg, const int len)
1291 {
1292         uint8_t buf[len + 3];
1293
1294         memset(buf, 0, sizeof(buf));
1295         if (len) {
1296                 buf[0] = '(';
1297                 memcpy(&buf[1], status_msg, len);
1298                 buf[len + 1] = ')';
1299         }
1300
1301         syslog(LOG_WARNING, "Server returned %s status %i %s",
1302                 scope, code, buf);
1303 }
1304
1305
1306 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1307                 const uint16_t code, const void *status_msg, const int len,
1308                 int *ret)
1309 {
1310         dhcpv6_log_status_code(code, "message", status_msg, len);
1311
1312         switch (code) {
1313         case DHCPV6_UnspecFail:
1314                 // Generic failure
1315                 *ret = 0;
1316                 break;
1317
1318         case DHCPV6_UseMulticast:
1319                 // TODO handle multicast status code
1320                 break;
1321
1322         case DHCPV6_NoAddrsAvail:
1323         case DHCPV6_NoPrefixAvail:
1324                 if (orig == DHCPV6_MSG_REQUEST)
1325                         *ret = 0; // Failure
1326                 break;
1327
1328         default:
1329                 break;
1330         }
1331 }
1332
1333
1334 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1335                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1336                 const void *status_msg, const int len,
1337                 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1338 {
1339         dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1340                 "IA_NA" : "IA_PD", status_msg, len);
1341
1342         switch (code) {
1343         case DHCPV6_NoBinding:
1344                 switch (orig) {
1345                 case DHCPV6_MSG_RENEW:
1346                 case DHCPV6_MSG_REBIND:
1347                         if ((*ret > 0) && !handled_status_codes[code])
1348                                 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1349                         break;
1350
1351                 default:
1352                         break;
1353                 }
1354                 break;
1355
1356         case DHCPV6_NoAddrsAvail:
1357         case DHCPV6_NoPrefixAvail:
1358                 switch (orig) {
1359                 case DHCPV6_MSG_REQUEST:
1360                         if (*ret != 0)
1361                                 *ret = 0;
1362                         break;
1363                 default:
1364                         break;
1365                 }
1366                 break;
1367
1368         case DHCPV6_NotOnLink:
1369                 // TODO handle not onlink in case of confirm
1370                 break;
1371
1372         default:
1373                 break;
1374         }
1375 }
1376
1377 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1378 {
1379         size_t cand_len, i;
1380         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1381
1382         // Remove identical duid server candidate
1383         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1384                 if (cand->duid_len == c[i].duid_len &&
1385                                 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1386                         free(c[i].ia_na);
1387                         free(c[i].ia_pd);
1388                         odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1389                         break;
1390                 }
1391         }
1392
1393         for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1394                 i < cand_len / sizeof(*c); ++i) {
1395                 if (c[i].preference < cand->preference)
1396                         break;
1397         }
1398
1399         odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand));
1400 }
1401
1402 static void dhcpv6_clear_all_server_cand(void)
1403 {
1404         size_t cand_len, i;
1405         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1406
1407         // Server candidates need deep delete for IA_NA/IA_PD
1408         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1409                 free(c[i].ia_na);
1410                 free(c[i].ia_pd);
1411         }
1412         odhcp6c_clear_state(STATE_SERVER_CAND);
1413 }
1414
1415 int dhcpv6_promote_server_cand(void)
1416 {
1417         size_t cand_len;
1418         struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1419         uint16_t hdr[2];
1420         int ret = DHCPV6_STATELESS;
1421
1422         // Clear lingering candidate state info
1423         odhcp6c_clear_state(STATE_SERVER_ID);
1424         odhcp6c_clear_state(STATE_IA_NA);
1425         odhcp6c_clear_state(STATE_IA_PD);
1426
1427         if (!cand_len)
1428                 return -1;
1429
1430         if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1431                 na_mode = IA_MODE_NONE;
1432
1433                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1434                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1435
1436                 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1437         }
1438
1439         hdr[0] = htons(DHCPV6_OPT_SERVERID);
1440         hdr[1] = htons(cand->duid_len);
1441         odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1442         odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1443         accept_reconfig = cand->wants_reconfigure;
1444         if (cand->ia_na_len) {
1445                 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1446                 free(cand->ia_na);
1447                 if (na_mode != IA_MODE_NONE)
1448                         ret = DHCPV6_STATEFUL;
1449         }
1450         if (cand->ia_pd_len) {
1451                 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1452                 free(cand->ia_pd);
1453                 if (request_prefix)
1454                         ret = DHCPV6_STATEFUL;
1455         }
1456
1457         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1458         dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1459
1460         odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1461
1462         return ret;
1463 }