src/dhcpv6.c

   1 /**
   2  * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License v2 as published by
   6  * the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  */
  14
  15 #include <time.h>
  16 #include <fcntl.h>
  17 #include <errno.h>
  18 #include <stdlib.h>
  19 #include <signal.h>
  20 #include <limits.h>
  21 #include <resolv.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24 #include <syslog.h>
  25 #include <stdbool.h>
  26 #include <sys/time.h>
  27 #include <sys/ioctl.h>
  28 #include <sys/socket.h>
  29 #include <netinet/in.h>
  30
  31 #include <net/if.h>
  32 #include <net/ethernet.h>
  33
  34 #include "odhcp6c.h"
  35 #include "md5.h"
  36
  37
  38 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
  39                 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
  40 #define DHCPV6_CLIENT_PORT 546
  41 #define DHCPV6_SERVER_PORT 547
  42 #define DHCPV6_DUID_LLADDR 3
  43 #define DHCPV6_REQ_DELAY 1
  44
  45 #define DHCPV6_SOL_MAX_RT_MIN 60
  46 #define DHCPV6_SOL_MAX_RT_MAX 86400
  47 #define DHCPV6_INF_MAX_RT_MIN 60
  48 #define DHCPV6_INF_MAX_RT_MAX 86400
  49
  50 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
  51                 const uint8_t transaction[3], enum dhcpv6_msg type,
  52                 const struct in6_addr *daddr);
  53
  54 static int dhcpv6_parse_ia(void *opt, void *end);
  55
  56 static int dhcpv6_calc_refresh_timers(void);
  57 static void dhcpv6_handle_status_code(_unused const enum dhcpv6_msg orig,
  58                 const uint16_t code, const void *status_msg, const int len,
  59                 int *ret);
  60 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
  61                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
  62                 const void *status_msg, const int len,
  63                 bool handled_status_codes[_DHCPV6_Status_Max],
  64                 int *ret);
  65 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand);
  66 static void dhcpv6_clear_all_server_cand(void);
  67
  68 static reply_handler dhcpv6_handle_reply;
  69 static reply_handler dhcpv6_handle_advert;
  70 static reply_handler dhcpv6_handle_rebind_reply;
  71 static reply_handler dhcpv6_handle_reconfigure;
  72 static int dhcpv6_commit_advert(void);
  73
  74
  75
  76 // RFC 3315 - 5.5 Timeout and Delay values
  77 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
  78         [DHCPV6_MSG_UNKNOWN] = {false, 1, 120, 0, "<POLL>",
  79                         dhcpv6_handle_reconfigure, NULL},
  80         [DHCPV6_MSG_SOLICIT] = {true, 1, DHCPV6_SOL_MAX_RT, 0, "SOLICIT",
  81                         dhcpv6_handle_advert, dhcpv6_commit_advert},
  82         [DHCPV6_MSG_REQUEST] = {true, 1, DHCPV6_REQ_MAX_RT, 10, "REQUEST",
  83                         dhcpv6_handle_reply, NULL},
  84         [DHCPV6_MSG_RENEW] = {false, 10, DHCPV6_REN_MAX_RT, 0, "RENEW",
  85                         dhcpv6_handle_reply, NULL},
  86         [DHCPV6_MSG_REBIND] = {false, 10, DHCPV6_REB_MAX_RT, 0, "REBIND",
  87                         dhcpv6_handle_rebind_reply, NULL},
  88         [DHCPV6_MSG_RELEASE] = {false, 1, 0, 5, "RELEASE", NULL, NULL},
  89         [DHCPV6_MSG_DECLINE] = {false, 1, 0, 5, "DECLINE", NULL, NULL},
  90         [DHCPV6_MSG_INFO_REQ] = {true, 1, DHCPV6_INF_MAX_RT, 0, "INFOREQ",
  91                         dhcpv6_handle_reply, NULL},
  92 };
  93
  94
  95 // Sockets
  96 static int sock = -1;
  97 static int ifindex = -1;
  98 static int64_t t1 = 0, t2 = 0, t3 = 0;
  99
 100 // IA states
 101 static int request_prefix = -1;
 102 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE;
 103 static bool accept_reconfig = false;
 104
 105 // Reconfigure key
 106 static uint8_t reconf_key[16];
 107
 108 // client options
 109 static unsigned int client_options = 0;
 110
 111
 112 int init_dhcpv6(const char *ifname, unsigned int options, int sol_timeout)
 113 {
 114         client_options = options;
 115         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
 116
 117         sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
 118         if (sock < 0)
 119                 return -1;
 120
 121         // Detect interface
 122         struct ifreq ifr;
 123         strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
 124         if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
 125                 return -1;
 126         ifindex = ifr.ifr_ifindex;
 127
 128         // Create client DUID
 129         size_t client_id_len;
 130         odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 131         if (client_id_len == 0) {
 132                 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
 133                                 DHCPV6_DUID_LLADDR, 0, 1};
 134
 135                 if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
 136                         memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
 137
 138                 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
 139                 struct ifreq ifs[100], *ifp, *ifend;
 140                 struct ifconf ifc;
 141                 ifc.ifc_req = ifs;
 142                 ifc.ifc_len = sizeof(ifs);
 143
 144                 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
 145                                 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
 146                         // If our interface doesn't have an address...
 147                         ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
 148                         for (ifp = ifc.ifc_req; ifp < ifend &&
 149                                         !memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
 150                                 memcpy(ifr.ifr_name, ifp->ifr_name,
 151                                                 sizeof(ifr.ifr_name));
 152                                 if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
 153                                         continue;
 154
 155                                 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
 156                                                 ETHER_ADDR_LEN);
 157                         }
 158                 }
 159
 160                 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
 161         }
 162
 163         // Create ORO
 164         if (!(client_options & DHCPV6_STRICT_OPTIONS)) {
 165                 uint16_t oro[] = {
 166                         htons(DHCPV6_OPT_SIP_SERVER_D),
 167                         htons(DHCPV6_OPT_SIP_SERVER_A),
 168                         htons(DHCPV6_OPT_DNS_SERVERS),
 169                         htons(DHCPV6_OPT_DNS_DOMAIN),
 170                         htons(DHCPV6_OPT_SNTP_SERVERS),
 171                         htons(DHCPV6_OPT_NTP_SERVER),
 172                         htons(DHCPV6_OPT_AFTR_NAME),
 173                         htons(DHCPV6_OPT_PD_EXCLUDE),
 174                         htons(DHCPV6_OPT_SOL_MAX_RT),
 175                         htons(DHCPV6_OPT_INF_MAX_RT),
 176 #ifdef EXT_CER_ID
 177                         htons(DHCPV6_OPT_CER_ID),
 178 #endif
 179                         htons(DHCPV6_OPT_S46_CONT_MAPE),
 180                         htons(DHCPV6_OPT_S46_CONT_MAPT),
 181                         htons(DHCPV6_OPT_S46_CONT_LW),
 182                 };
 183                 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
 184         }
 185
 186         // Configure IPv6-options
 187         int val = 1;
 188         setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
 189         setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
 190         setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
 191         setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
 192
 193         struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
 194                 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
 195         if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
 196                 return -1;
 197
 198         return 0;
 199 }
 200
 201 enum {
 202         IOV_HDR=0,
 203         IOV_ORO,
 204         IOV_ORO_REFRESH,
 205         IOV_CL_ID,
 206         IOV_SRV_ID,
 207         IOV_VENDOR_CLASS_HDR,
 208         IOV_VENDOR_CLASS,
 209         IOV_USER_CLASS_HDR,
 210         IOV_USER_CLASS,
 211         IOV_RECONF_ACCEPT,
 212         IOV_FQDN,
 213         IOV_HDR_IA_NA,
 214         IOV_IA_NA,
 215         IOV_IA_PD,
 216         IOV_TOTAL
 217 };
 218
 219 void dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
 220 {
 221         na_mode = na;
 222         pd_mode = pd;
 223 }
 224
 225 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
 226 {
 227         // Build FQDN
 228         char fqdn_buf[256];
 229         gethostname(fqdn_buf, sizeof(fqdn_buf));
 230         struct {
 231                 uint16_t type;
 232                 uint16_t len;
 233                 uint8_t flags;
 234                 uint8_t data[256];
 235         } fqdn;
 236         size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
 237                         sizeof(fqdn.data), NULL, NULL);
 238         fqdn.type = htons(DHCPV6_OPT_FQDN);
 239         fqdn.len = htons(fqdn_len - 4);
 240         fqdn.flags = 0;
 241
 242
 243         // Build Client ID
 244         size_t cl_id_len;
 245         void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
 246
 247         // Get Server ID
 248         size_t srv_id_len;
 249         void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
 250
 251         // Build IA_PDs
 252         size_t ia_pd_entries = 0, ia_pd_len = 0;
 253         uint8_t *ia_pd;
 254
 255         if (type == DHCPV6_MSG_SOLICIT) {
 256                 odhcp6c_clear_state(STATE_IA_PD);
 257                 size_t n_prefixes;
 258                 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
 259                 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
 260
 261                 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
 262
 263                 for (size_t i = 0; i < n_prefixes; i++) {
 264                         struct dhcpv6_ia_hdr hdr_ia_pd = {
 265                                 htons(DHCPV6_OPT_IA_PD),
 266                                 htons(sizeof(hdr_ia_pd) - 4 + sizeof(struct dhcpv6_ia_prefix)),
 267                                 request_prefixes[i].iaid, 0, 0
 268                         };
 269                         struct dhcpv6_ia_prefix pref = {
 270                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 271                                 .len = htons(25), .prefix = request_prefixes[i].length
 272                         };
 273                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
 274                         ia_pd_len += sizeof(hdr_ia_pd);
 275                         memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
 276                         ia_pd_len += sizeof(pref);
 277                 }
 278         } else {
 279                 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
 280                 ia_pd_entries /= sizeof(*e);
 281
 282                 // we're too lazy to count our distinct IAIDs,
 283                 // so just allocate maximally needed space
 284                 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
 285                                         sizeof(struct dhcpv6_ia_hdr)));
 286
 287                 for (size_t i = 0; i < ia_pd_entries; ++i) {
 288                         uint32_t iaid = e[i].iaid;
 289
 290                         // check if this is an unprocessed IAID and skip if not.
 291                         int new_iaid = 1;
 292                         for (int j = i-1; j >= 0; j--) {
 293                                 if (e[j].iaid == iaid) {
 294                                         new_iaid = 0;
 295                                         break;
 296                                 }
 297                         }
 298
 299                         if (!new_iaid)
 300                                 continue;
 301
 302                         // construct header
 303                         struct dhcpv6_ia_hdr hdr_ia_pd = {
 304                                 htons(DHCPV6_OPT_IA_PD),
 305                                 htons(sizeof(hdr_ia_pd) - 4),
 306                                 iaid, 0, 0
 307                         };
 308
 309                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
 310                         struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
 311                         ia_pd_len += sizeof(hdr_ia_pd);
 312
 313                         for (size_t j = i; j < ia_pd_entries; j++) {
 314                                 if (e[j].iaid != iaid)
 315                                         continue;
 316
 317                                 uint8_t ex_len = 0;
 318                                 if (e[j].priority > 0)
 319                                         ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
 320
 321                                 struct dhcpv6_ia_prefix p = {
 322                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 323                                         .len = htons(sizeof(p) - 4U + ex_len),
 324                                         .prefix = e[j].length,
 325                                         .addr = e[j].target
 326                                 };
 327
 328                                 if (type == DHCPV6_MSG_REQUEST) {
 329                                         p.preferred = htonl(e[j].preferred);
 330                                         p.valid = htonl(e[j].valid);
 331                                 }
 332
 333                                 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
 334                                 ia_pd_len += sizeof(p);
 335
 336                                 if (ex_len) {
 337                                         ia_pd[ia_pd_len++] = 0;
 338                                         ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
 339                                         ia_pd[ia_pd_len++] = 0;
 340                                         ia_pd[ia_pd_len++] = ex_len - 4;
 341                                         ia_pd[ia_pd_len++] = e[j].priority;
 342
 343                                         uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
 344                                         excl >>= (64 - e[j].priority);
 345                                         excl <<= 8 - ((e[j].priority - e[j].length) % 8);
 346
 347                                         for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
 348                                                 ia_pd[ia_pd_len + i] = excl & 0xff;
 349                                         ia_pd_len += ex_len - 5;
 350                                 }
 351
 352                                 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
 353                         }
 354                 }
 355         }
 356
 357         if (ia_pd_entries > 0)
 358                 request_prefix = 1;
 359
 360         // Build IA_NAs
 361         size_t ia_na_entries, ia_na_len = 0;
 362         void *ia_na = NULL;
 363         struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
 364         ia_na_entries /= sizeof(*e);
 365
 366         struct dhcpv6_ia_hdr hdr_ia_na = {
 367                 htons(DHCPV6_OPT_IA_NA),
 368                 htons(sizeof(hdr_ia_na) - 4),
 369                 htonl(1), 0, 0
 370         };
 371
 372         struct dhcpv6_ia_addr pa[ia_na_entries];
 373         for (size_t i = 0; i < ia_na_entries; ++i) {
 374                 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
 375                 pa[i].len = htons(sizeof(pa[i]) - 4U);
 376                 pa[i].addr = e[i].target;
 377
 378                 if (type == DHCPV6_MSG_REQUEST) {
 379                         pa[i].preferred = htonl(e[i].preferred);
 380                         pa[i].valid = htonl(e[i].valid);
 381                 } else {
 382                         pa[i].preferred = 0;
 383                         pa[i].valid = 0;
 384                 }
 385         }
 386
 387         ia_na = pa;
 388         ia_na_len = sizeof(pa);
 389         hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
 390
 391         // Reconfigure Accept
 392         struct {
 393                 uint16_t type;
 394                 uint16_t length;
 395         } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
 396
 397         // Request Information Refresh
 398         uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
 399
 400         // Build vendor-class option
 401         size_t vendor_class_len, user_class_len;
 402         struct dhcpv6_vendorclass *vendor_class = odhcp6c_get_state(STATE_VENDORCLASS, &vendor_class_len);
 403         void *user_class = odhcp6c_get_state(STATE_USERCLASS, &user_class_len);
 404
 405         struct {
 406                 uint16_t type;
 407                 uint16_t length;
 408         } vendor_class_hdr = {htons(DHCPV6_OPT_VENDOR_CLASS), htons(vendor_class_len)};
 409
 410         struct {
 411                 uint16_t type;
 412                 uint16_t length;
 413         } user_class_hdr = {htons(DHCPV6_OPT_USER_CLASS), htons(user_class_len)};
 414
 415         // Prepare Header
 416         size_t oro_len;
 417         void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
 418         struct {
 419                 uint8_t type;
 420                 uint8_t trid[3];
 421                 uint16_t elapsed_type;
 422                 uint16_t elapsed_len;
 423                 uint16_t elapsed_value;
 424                 uint16_t oro_type;
 425                 uint16_t oro_len;
 426         } hdr = {
 427                 type, {trid[0], trid[1], trid[2]},
 428                 htons(DHCPV6_OPT_ELAPSED), htons(2),
 429                         htons((ecs > 0xffff) ? 0xffff : ecs),
 430                 htons(DHCPV6_OPT_ORO), htons(oro_len),
 431         };
 432
 433         struct iovec iov[IOV_TOTAL] = {
 434                 [IOV_HDR] = {&hdr, sizeof(hdr)},
 435                 [IOV_ORO] = {oro, oro_len},
 436                 [IOV_ORO_REFRESH] = {&oro_refresh, 0},
 437                 [IOV_CL_ID] = {cl_id, cl_id_len},
 438                 [IOV_SRV_ID] = {srv_id, srv_id_len},
 439                 [IOV_VENDOR_CLASS_HDR] = {&vendor_class_hdr, vendor_class_len ? sizeof(vendor_class_hdr) : 0},
 440                 [IOV_VENDOR_CLASS] = {vendor_class, vendor_class_len},
 441                 [IOV_USER_CLASS_HDR] = {&user_class_hdr, user_class_len ? sizeof(user_class_hdr) : 0},
 442                 [IOV_USER_CLASS] = {user_class, user_class_len},
 443                 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
 444                 [IOV_FQDN] = {&fqdn, fqdn_len},
 445                 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
 446                 [IOV_IA_NA] = {ia_na, ia_na_len},
 447                 [IOV_IA_PD] = {ia_pd, ia_pd_len},
 448         };
 449
 450         size_t cnt = IOV_TOTAL;
 451         if (type == DHCPV6_MSG_INFO_REQ) {
 452                 cnt = 9;
 453                 iov[IOV_ORO_REFRESH].iov_len = sizeof(oro_refresh);
 454                 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
 455         } else if (!request_prefix) {
 456                 cnt = 13;
 457         }
 458
 459         // Disable IAs if not used
 460         if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
 461                 iov[IOV_HDR_IA_NA].iov_len = 0;
 462
 463         if (na_mode == IA_MODE_NONE)
 464                 iov[IOV_HDR_IA_NA].iov_len = 0;
 465
 466         if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
 467                         !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
 468                 iov[IOV_RECONF_ACCEPT].iov_len = 0;
 469
 470         if (!(client_options & DHCPV6_CLIENT_FQDN))
 471                 iov[IOV_FQDN].iov_len = 0;
 472
 473         struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
 474                 0, ALL_DHCPV6_RELAYS, ifindex};
 475         struct msghdr msg = {.msg_name = &srv, .msg_namelen = sizeof(srv),
 476                         .msg_iov = iov, .msg_iovlen = cnt};
 477
 478         sendmsg(sock, &msg, 0);
 479 }
 480
 481
 482 static int64_t dhcpv6_rand_delay(int64_t time)
 483 {
 484         int random;
 485         odhcp6c_random(&random, sizeof(random));
 486         return (time * ((int64_t)random % 1000LL)) / 10000LL;
 487 }
 488
 489
 490 int dhcpv6_request(enum dhcpv6_msg type)
 491 {
 492         uint8_t rc = 0;
 493         uint64_t timeout = UINT32_MAX;
 494         struct dhcpv6_retx *retx = &dhcpv6_retx[type];
 495
 496         if (retx->delay) {
 497                 struct timespec ts = {0, 0};
 498                 ts.tv_nsec = (dhcpv6_rand_delay((10000 * DHCPV6_REQ_DELAY) / 2) + (1000 * DHCPV6_REQ_DELAY) / 2) * 1000000;
 499                 while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
 500         }
 501
 502         if (type == DHCPV6_MSG_UNKNOWN)
 503                 timeout = t1;
 504         else if (type == DHCPV6_MSG_RENEW)
 505                 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
 506         else if (type == DHCPV6_MSG_REBIND)
 507                 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
 508
 509         if (timeout == 0)
 510                 return -1;
 511
 512         syslog(LOG_NOTICE, "Starting %s transaction (timeout %llus, max rc %d)",
 513                         retx->name, (unsigned long long)timeout, retx->max_rc);
 514
 515         uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
 516
 517         // Generate transaction ID
 518         uint8_t trid[3] = {0, 0, 0};
 519         if (type != DHCPV6_MSG_UNKNOWN)
 520                 odhcp6c_random(trid, sizeof(trid));
 521         ssize_t len = -1;
 522         int64_t rto = 0;
 523
 524         do {
 525                 if (rto == 0) {
 526                         int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 527
 528                         // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
 529                         while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
 530                                 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 531
 532                         rto = (retx->init_timeo * 1000 + delay);
 533                 }
 534                 else
 535                         rto = (2 * rto + dhcpv6_rand_delay(rto));
 536
 537                 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
 538                         rto = retx->max_timeo * 1000 +
 539                                 dhcpv6_rand_delay(retx->max_timeo * 1000);
 540
 541                 // Calculate end for this round and elapsed time
 542                 uint64_t round_end = round_start + rto;
 543                 elapsed = round_start - start;
 544
 545                 // Don't wait too long if timeout differs from infinite
 546                 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
 547                         round_end = timeout * 1000 + start;
 548
 549                 // Built and send package
 550                 if (type != DHCPV6_MSG_UNKNOWN) {
 551                         if (type != DHCPV6_MSG_SOLICIT)
 552                                 syslog(LOG_NOTICE, "Send %s message (elapsed %llums, rc %d)",
 553                                                 retx->name, (unsigned long long)elapsed, rc);
 554                         dhcpv6_send(type, trid, elapsed / 10);
 555                         rc++;
 556                 }
 557
 558                 // Receive rounds
 559                 for (; len < 0 && (round_start < round_end);
 560                                 round_start = odhcp6c_get_milli_time()) {
 561                         uint8_t buf[1536], cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
 562                         struct iovec iov = {buf, sizeof(buf)};
 563                         struct sockaddr_in6 addr;
 564                         struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr),
 565                                         .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf,
 566                                         .msg_controllen = sizeof(cmsg_buf)};
 567                         struct in6_pktinfo *pktinfo = NULL;
 568
 569
 570                         // Check for pending signal
 571                         if (odhcp6c_signal_process())
 572                                 return -1;
 573
 574                         // Set timeout for receiving
 575                         uint64_t t = round_end - round_start;
 576                         struct timeval tv = {t / 1000, (t % 1000) * 1000};
 577                         setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
 578                                         &tv, sizeof(tv));
 579
 580                         // Receive cycle
 581                         len = recvmsg(sock, &msg, 0);
 582                         if (len < 0)
 583                                 continue;
 584
 585                         for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
 586                                 ch = CMSG_NXTHDR(&msg, ch)) {
 587                                 if (ch->cmsg_level == SOL_IPV6 &&
 588                                         ch->cmsg_type == IPV6_PKTINFO) {
 589                                         pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
 590                                         break;
 591                                 }
 592                         }
 593
 594                         if (pktinfo == NULL) {
 595                                 len = -1;
 596                                 continue;
 597                         }
 598
 599                         if (!dhcpv6_response_is_valid(buf, len, trid,
 600                                                         type, &pktinfo->ipi6_addr)) {
 601                                 len = -1;
 602                                 continue;
 603                         }
 604
 605                         uint8_t *opt = &buf[4];
 606                         uint8_t *opt_end = opt + len - 4;
 607
 608                         round_start = odhcp6c_get_milli_time();
 609                         elapsed = round_start - start;
 610                         syslog(LOG_NOTICE, "Got a valid reply after "
 611                                         "%llums", (unsigned long long)elapsed);
 612
 613                         if (retx->handler_reply)
 614                                 len = retx->handler_reply(type, rc, opt, opt_end, &addr);
 615
 616                         if (len > 0 && round_end - round_start > 1000)
 617                                 round_end = 1000 + round_start;
 618                 }
 619
 620                 // Allow
 621                 if (retx->handler_finish)
 622                         len = retx->handler_finish();
 623         } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
 624                         (!retx->max_rc || rc < retx->max_rc));
 625         return len;
 626 }
 627
 628 // Message validation checks according to RFC3315 chapter 15
 629 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
 630                 const uint8_t transaction[3], enum dhcpv6_msg type,
 631                 const struct in6_addr *daddr)
 632 {
 633         const struct dhcpv6_header *rep = buf;
 634         if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
 635                         transaction, sizeof(rep->tr_id)))
 636                 return false; // Invalid reply
 637
 638         if (type == DHCPV6_MSG_SOLICIT) {
 639                 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
 640                                 rep->msg_type != DHCPV6_MSG_REPLY)
 641                         return false;
 642         } else if (type == DHCPV6_MSG_UNKNOWN) {
 643                 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
 644                         return false;
 645         } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
 646                 return false;
 647         }
 648
 649         uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
 650                 rcmsg = DHCPV6_MSG_UNKNOWN;
 651         uint16_t otype, olen = UINT16_MAX;
 652         bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
 653                 ia_present = false, options_valid = true;
 654
 655         size_t client_id_len, server_id_len;
 656         void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 657         void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 658
 659         dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
 660                 if (otype == DHCPV6_OPT_CLIENTID) {
 661                         clientid_ok = (olen + 4U == client_id_len) && !memcmp(
 662                                         &odata[-4], client_id, client_id_len);
 663                 } else if (otype == DHCPV6_OPT_SERVERID) {
 664                         if (server_id_len)
 665                                 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
 666                                                 &odata[-4], server_id, server_id_len);
 667                         else
 668                                 serverid_ok = true;
 669                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
 670                                 sizeof(struct dhcpv6_auth_reconfigure)) {
 671                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
 672                         if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
 673                                 continue;
 674
 675                         md5_ctx_t md5;
 676                         uint8_t serverhash[16], secretbytes[64], hash[16];
 677                         memcpy(serverhash, r->key, sizeof(serverhash));
 678                         memset(r->key, 0, sizeof(r->key));
 679
 680                         memset(secretbytes, 0, sizeof(secretbytes));
 681                         memcpy(secretbytes, reconf_key, sizeof(reconf_key));
 682
 683                         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 684                                 secretbytes[i] ^= 0x36;
 685
 686                         md5_begin(&md5);
 687                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 688                         md5_hash(buf, len, &md5);
 689                         md5_end(hash, &md5);
 690
 691                         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 692                                 secretbytes[i] ^= 0x36;
 693                                 secretbytes[i] ^= 0x5c;
 694                         }
 695
 696                         md5_begin(&md5);
 697                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 698                         md5_hash(hash, 16, &md5);
 699                         md5_end(hash, &md5);
 700
 701                         rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
 702                 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
 703                         rcmsg = odata[0];
 704                 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
 705                         ia_present = true;
 706                         if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
 707                                 options_valid = false;
 708                 }
 709                 else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
 710                                 (otype == DHCPV6_OPT_PD_EXCLUDE)) {
 711                         // Options are not allowed on global level
 712                         options_valid = false;
 713                 }
 714         }
 715
 716         if (!options_valid || ((odata + olen) > end))
 717                 return false;
 718
 719         if (type == DHCPV6_MSG_INFO_REQ && ia_present)
 720                 return false;
 721
 722         if (rep->msg_type == DHCPV6_MSG_RECONF) {
 723                 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
 724                         (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
 725                         !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
 726                         return false;
 727         }
 728
 729         return clientid_ok && serverid_ok;
 730 }
 731
 732
 733 int dhcpv6_poll_reconfigure(void)
 734 {
 735         int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
 736         if (ret != -1)
 737                 ret = dhcpv6_request(ret);
 738
 739         return ret;
 740 }
 741
 742
 743 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
 744                 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
 745 {
 746         uint16_t otype, olen;
 747         uint8_t *odata, msg = DHCPV6_MSG_RENEW;
 748         dhcpv6_for_each_option(opt, end, otype, olen, odata)
 749                 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
 750                                 odata[0] == DHCPV6_MSG_RENEW ||
 751                                 odata[0] == DHCPV6_MSG_INFO_REQ))
 752                         msg = odata[0];
 753
 754         dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL, NULL);
 755         return msg;
 756 }
 757
 758
 759 // Collect all advertised servers
 760 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
 761                 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
 762 {
 763         uint16_t olen, otype;
 764         uint8_t *odata, pref = 0;
 765         struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
 766                                         DHCPV6_SOL_MAX_RT,
 767                                         DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
 768         bool have_na = false;
 769         int have_pd = 0;
 770
 771         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 772                 if (orig == DHCPV6_MSG_SOLICIT &&
 773                                 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
 774                                 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
 775                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 776                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 777                 }
 778
 779                 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
 780                         memcpy(cand.duid, odata, olen);
 781                         cand.duid_len = olen;
 782                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
 783                         int error = ((int)odata[0] << 8 | (int)odata[1]);
 784
 785                         switch (error) {
 786                         case DHCPV6_NoPrefixAvail:
 787                                 // Status code on global level
 788                                 cand.preference -= 2000;
 789                                 break;
 790
 791                         default :
 792                                 break;
 793                         }
 794                 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
 795                                 cand.preference >= 0) {
 796                         cand.preference = pref = odata[0];
 797                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 798                         cand.wants_reconfigure = true;
 799                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
 800                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
 801                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
 802                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
 803                                 cand.sol_max_rt = sol_max_rt;
 804                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
 805                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
 806                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
 807                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
 808                                 cand.inf_max_rt = inf_max_rt;
 809                 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
 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_PREFIX &&
 814                                                 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
 815                                         struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
 816                                         have_pd = p->prefix;
 817                                 }
 818                         }
 819                 } else if (otype == DHCPV6_OPT_IA_NA) {
 820                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 821                         uint8_t *oend = odata + olen, *d;
 822                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
 823                                 if (otype == DHCPV6_OPT_IA_ADDR &&
 824                                                 olen >= -4 + sizeof(struct dhcpv6_ia_addr))
 825                                         have_na = true;
 826                 }
 827         }
 828
 829         if ((!have_na && na_mode == IA_MODE_FORCE) ||
 830                         (!have_pd && pd_mode == IA_MODE_FORCE)) {
 831                 /*
 832                  * RFC7083 states to process the SOL_MAX_RT and
 833                  * INF_MAX_RT options even if the DHCPv6 server
 834                  * did not propose any IA_NA and/or IA_PD
 835                  */
 836                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
 837                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
 838                 return -1;
 839         }
 840
 841         if (na_mode != IA_MODE_NONE && !have_na) {
 842                 cand.has_noaddravail = true;
 843                 cand.preference -= 1000;
 844         }
 845
 846         if (pd_mode != IA_MODE_NONE) {
 847                 if (have_pd)
 848                         cand.preference += 2000 + (128 - have_pd);
 849                 else
 850                         cand.preference -= 2000;
 851         }
 852
 853         if (cand.duid_len > 0) {
 854                 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
 855                 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
 856                 dhcpv6_add_server_cand(&cand);
 857         }
 858
 859         return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
 860 }
 861
 862
 863 static int dhcpv6_commit_advert(void)
 864 {
 865         return dhcpv6_promote_server_cand();
 866 }
 867
 868
 869 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
 870                 const void *opt, const void *end, const struct sockaddr_in6 *from)
 871 {
 872         dhcpv6_handle_advert(orig, rc, opt, end, from);
 873         if (dhcpv6_commit_advert() < 0)
 874                 return -1;
 875
 876         return dhcpv6_handle_reply(orig, rc, opt, end, from);
 877 }
 878
 879
 880 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
 881                 const void *opt, const void *end, const struct sockaddr_in6 *from)
 882 {
 883         uint8_t *odata;
 884         uint16_t otype, olen;
 885         uint32_t refresh = 86400;
 886         int ret = 1;
 887         bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
 888
 889         odhcp6c_expire();
 890
 891         if (orig == DHCPV6_MSG_UNKNOWN) {
 892                 static time_t last_update = 0;
 893                 time_t now = odhcp6c_get_milli_time() / 1000;
 894
 895                 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 896                 last_update = now;
 897
 898                 if (t1 != UINT32_MAX)
 899                         t1 -= elapsed;
 900
 901                 if (t2 != UINT32_MAX)
 902                         t2 -= elapsed;
 903
 904                 if (t3 != UINT32_MAX)
 905                         t3 -= elapsed;
 906
 907                 if (t1 < 0)
 908                         t1 = 0;
 909
 910                 if (t2 < 0)
 911                         t2 = 0;
 912
 913                 if (t3 < 0)
 914                         t3 = 0;
 915         }
 916
 917         if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
 918                 // Delete NA and PD we have in the state from the Advert
 919                 odhcp6c_clear_state(STATE_IA_NA);
 920                 odhcp6c_clear_state(STATE_IA_PD);
 921         }
 922
 923         if (opt) {
 924                 odhcp6c_clear_state(STATE_DNS);
 925                 odhcp6c_clear_state(STATE_SEARCH);
 926                 odhcp6c_clear_state(STATE_SNTP_IP);
 927                 odhcp6c_clear_state(STATE_NTP_IP);
 928                 odhcp6c_clear_state(STATE_NTP_FQDN);
 929                 odhcp6c_clear_state(STATE_SIP_IP);
 930                 odhcp6c_clear_state(STATE_SIP_FQDN);
 931                 odhcp6c_clear_state(STATE_AFTR_NAME);
 932                 odhcp6c_clear_state(STATE_CER);
 933                 odhcp6c_clear_state(STATE_S46_MAPT);
 934                 odhcp6c_clear_state(STATE_S46_MAPE);
 935                 odhcp6c_clear_state(STATE_S46_LW);
 936                 odhcp6c_clear_state(STATE_PASSTHRU);
 937         }
 938
 939         // Parse and find all matching IAs
 940         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 941                 bool passthru = true;
 942
 943                 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
 944                                 && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
 945                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 946
 947                         if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) ||
 948                             (pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD))
 949                                 continue;
 950
 951                         // Test ID
 952                         if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
 953                                 continue;
 954
 955                         uint16_t code = DHCPV6_Success;
 956                         uint16_t stype, slen;
 957                         uint8_t *sdata;
 958                         // Get and handle status code
 959                         dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
 960                                         stype, slen, sdata) {
 961                                 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
 962                                         uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
 963                                         uint16_t mlen = (slen > 2) ? slen - 2 : 0;
 964
 965                                         code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
 966
 967                                         if (code == DHCPV6_Success)
 968                                                 continue;
 969
 970                                         dhcpv6_handle_ia_status_code(orig, ia_hdr,
 971                                                 code, mdata, mlen, handled_status_codes, &ret);
 972
 973
 974                                         if (ret > 0)
 975                                                 return ret;
 976                                         break;
 977                                 }
 978                         }
 979
 980                         if (code != DHCPV6_Success)
 981                                 continue;
 982
 983                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 984                         passthru = false;
 985                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
 986                         uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
 987                         uint16_t mlen = (olen > 2) ? olen - 2 : 0;
 988                         uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
 989
 990                         dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
 991                         passthru = false;
 992                 }
 993                 else if (otype == DHCPV6_OPT_DNS_SERVERS) {
 994                         if (olen % 16 == 0)
 995                                 odhcp6c_add_state(STATE_DNS, odata, olen);
 996                 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
 997                         odhcp6c_add_state(STATE_SEARCH, odata, olen);
 998                         passthru = false;
 999                 } else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
1000                         if (olen % 16 == 0)
1001                                 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
1002                 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
1003                         uint16_t stype, slen;
1004                         uint8_t *sdata;
1005                         // Test status and bail if error
1006                         dhcpv6_for_each_option(odata, odata + olen,
1007                                         stype, slen, sdata) {
1008                                 if (slen == 16 && (stype == NTP_MC_ADDR ||
1009                                                 stype == NTP_SRV_ADDR))
1010                                         odhcp6c_add_state(STATE_NTP_IP,
1011                                                         sdata, slen);
1012                                 else if (slen > 0 && stype == NTP_SRV_FQDN)
1013                                         odhcp6c_add_state(STATE_NTP_FQDN,
1014                                                         sdata, slen);
1015                         }
1016                 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1017                         if (olen == 16)
1018                                 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1019                 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
1020                         odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1021                 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1022                         refresh = ntohl(*((uint32_t*)odata));
1023                         passthru = false;
1024                 } else if (otype == DHCPV6_OPT_AUTH) {
1025                         if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1026                                 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1027                                 if (r->protocol == 3 && r->algorithm == 1 &&
1028                                                 r->reconf_type == 1)
1029                                         memcpy(reconf_key, r->key, sizeof(r->key));
1030                         }
1031                         passthru = false;
1032                 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1033                         size_t cur_len;
1034                         odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1035                         if (cur_len == 0)
1036                                 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1037                         passthru = false;
1038                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1039                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
1040                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1041                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1042                                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1043                         passthru = false;
1044                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1045                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
1046                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1047                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1048                                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1049                         passthru = false;
1050 #ifdef EXT_CER_ID
1051                 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1052                                 sizeof(struct dhcpv6_cer_id)) {
1053                         struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1054                         struct in6_addr any = IN6ADDR_ANY_INIT;
1055                         if (memcmp(&cer_id->addr, &any, sizeof(any)))
1056                                 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1057                         passthru = false;
1058 #endif
1059                 } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1060                         odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1061                         passthru = false;
1062                 } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1063                         size_t mape_len;
1064                         odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1065                         if (mape_len == 0)
1066                                 odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1067                         passthru = false;
1068                 } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1069                         odhcp6c_add_state(STATE_S46_LW, odata, olen);
1070                         passthru = false;
1071                 } else if (otype == DHCPV6_OPT_CLIENTID ||
1072                                 otype == DHCPV6_OPT_SERVERID ||
1073                                 otype == DHCPV6_OPT_IA_TA ||
1074                                 otype == DHCPV6_OPT_PREF ||
1075                                 otype == DHCPV6_OPT_UNICAST ||
1076                                 otype == DHCPV6_OPT_FQDN ||
1077                                 otype == DHCPV6_OPT_RECONF_ACCEPT) {
1078                         passthru = false;
1079                 } else {
1080                         odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1081                 }
1082
1083                 if (passthru)
1084                         odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1085         }
1086
1087         if (orig != DHCPV6_MSG_INFO_REQ) {
1088                 // Update refresh timers if no fatal status code was received
1089                 if ((ret > 0) && dhcpv6_calc_refresh_timers()) {
1090                         switch (orig) {
1091                         case DHCPV6_MSG_RENEW:
1092                                 // Send further renews if T1 is not set
1093                                 if (!t1)
1094                                         ret = -1;
1095                                 break;
1096                         case DHCPV6_MSG_REBIND:
1097                                 // Send further rebinds if T1 and T2 is not set
1098                                 if (!t1 && !t2)
1099                                         ret = -1;
1100                                 break;
1101
1102                         case DHCPV6_MSG_REQUEST:
1103                                 // All server candidates can be cleared if not yet bound
1104                                 if (!odhcp6c_is_bound())
1105                                         dhcpv6_clear_all_server_cand();
1106
1107                         default :
1108                                 break;
1109                         }
1110
1111                         if (orig == DHCPV6_MSG_REBIND || orig == DHCPV6_MSG_REQUEST) {
1112                                 odhcp6c_clear_state(STATE_SERVER_ADDR);
1113                                 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1114                         }
1115                 }
1116         }
1117         else if (ret > 0) {
1118                 // All server candidates can be cleared if not yet bound
1119                 if (!odhcp6c_is_bound())
1120                         dhcpv6_clear_all_server_cand();
1121
1122                 t1 = refresh;
1123         }
1124
1125         return ret;
1126 }
1127
1128
1129 static int dhcpv6_parse_ia(void *opt, void *end)
1130 {
1131         struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1132         int parsed_ia = 0;
1133         uint32_t t1, t2;
1134         uint16_t otype, olen;
1135         uint8_t *odata;
1136
1137         t1 = ntohl(ia_hdr->t1);
1138         t2 = ntohl(ia_hdr->t2);
1139
1140         if (t1 > t2)
1141                 return 0;
1142
1143         // Update address IA
1144         dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1145                 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
1146                                 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0};
1147
1148                 entry.iaid = ia_hdr->iaid;
1149
1150                 if (otype == DHCPV6_OPT_IA_PREFIX) {
1151                         struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1152                         if (olen + 4U < sizeof(*prefix))
1153                                 continue;
1154
1155                         entry.valid = ntohl(prefix->valid);
1156                         entry.preferred = ntohl(prefix->preferred);
1157
1158                         if (entry.preferred > entry.valid)
1159                                 continue;
1160
1161                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1162                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1163                         if (entry.t1 > entry.t2)
1164                                 entry.t1 = entry.t2;
1165
1166                         entry.length = prefix->prefix;
1167                         entry.target = prefix->addr;
1168                         uint16_t stype, slen;
1169                         uint8_t *sdata;
1170
1171                         // Parse PD-exclude
1172                         bool ok = true;
1173                         dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1174                                         odata + olen, stype, slen, sdata) {
1175                                 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1176                                         continue;
1177
1178                                 uint8_t elen = sdata[0];
1179                                 if (elen > 64)
1180                                         elen = 64;
1181
1182                                 if (elen <= 32 || elen <= entry.length) {
1183                                         ok = false;
1184                                         continue;
1185                                 }
1186
1187
1188                                 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1189                                 if (slen <= bytes) {
1190                                         ok = false;
1191                                         continue;
1192                                 }
1193
1194                                 uint32_t exclude = 0;
1195                                 do {
1196                                         exclude = exclude << 8 | sdata[bytes];
1197                                 } while (--bytes);
1198
1199                                 exclude >>= 8 - ((elen - entry.length) % 8);
1200                                 exclude <<= 64 - elen;
1201
1202                                 // Abusing router & priority fields for exclusion
1203                                 entry.router = entry.target;
1204                                 entry.router.s6_addr32[1] |= htonl(exclude);
1205                                 entry.priority = elen;
1206                         }
1207
1208                         if (ok) {
1209                                 odhcp6c_update_entry(STATE_IA_PD, &entry, 0, false);
1210                                 parsed_ia++;
1211                         }
1212
1213                         entry.priority = 0;
1214                         memset(&entry.router, 0, sizeof(entry.router));
1215                 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1216                         struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1217                         if (olen + 4U < sizeof(*addr))
1218                                 continue;
1219
1220                         entry.preferred = ntohl(addr->preferred);
1221                         entry.valid = ntohl(addr->valid);
1222
1223                         if (entry.preferred > entry.valid)
1224                                 continue;
1225
1226                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1227                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1228                         if (entry.t1 > entry.t2)
1229                                 entry.t1 = entry.t2;
1230
1231                         entry.length = 128;
1232                         entry.target = addr->addr;
1233
1234                         odhcp6c_update_entry(STATE_IA_NA, &entry, 0, false);
1235                         parsed_ia++;
1236                 }
1237         }
1238         return parsed_ia;
1239 }
1240
1241
1242 static int dhcpv6_calc_refresh_timers(void)
1243 {
1244         struct odhcp6c_entry *e;
1245         size_t ia_na_entries, ia_pd_entries, i;
1246         int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1247
1248         e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1249         ia_na_entries /= sizeof(*e);
1250         for (i = 0; i < ia_na_entries; i++) {
1251                 if (e[i].t1 < l_t1)
1252                         l_t1 = e[i].t1;
1253
1254                 if (e[i].t2 < l_t2)
1255                         l_t2 = e[i].t2;
1256
1257                 if (e[i].valid > l_t3)
1258                         l_t3 = e[i].valid;
1259         }
1260
1261         e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1262         ia_pd_entries /= sizeof(*e);
1263         for (i = 0; i < ia_pd_entries; i++) {
1264                 if (e[i].t1 < l_t1)
1265                         l_t1 = e[i].t1;
1266
1267                 if (e[i].t2 < l_t2)
1268                         l_t2 = e[i].t2;
1269
1270                 if (e[i].valid > l_t3)
1271                         l_t3 = e[i].valid;
1272         }
1273
1274         if (ia_pd_entries || ia_na_entries) {
1275                 t1 = l_t1;
1276                 t2 = l_t2;
1277                 t3 = l_t3;
1278         } else {
1279                 t1 = 600;
1280         }
1281
1282         return (int)(ia_pd_entries + ia_na_entries);
1283 }
1284
1285
1286 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1287                 const void *status_msg, const int len)
1288 {
1289         uint8_t buf[len + 3];
1290
1291         memset(buf, 0, sizeof(buf));
1292         if (len) {
1293                 buf[0] = '(';
1294                 memcpy(&buf[1], status_msg, len);
1295                 buf[len + 1] = ')';
1296         }
1297
1298         syslog(LOG_WARNING, "Server returned %s status %i %s",
1299                 scope, code, buf);
1300 }
1301
1302
1303 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1304                 const uint16_t code, const void *status_msg, const int len,
1305                 int *ret)
1306 {
1307         dhcpv6_log_status_code(code, "message", status_msg, len);
1308
1309         switch (code) {
1310         case DHCPV6_UnspecFail:
1311                 // Generic failure
1312                 *ret = 0;
1313                 break;
1314
1315         case DHCPV6_UseMulticast:
1316                 // TODO handle multicast status code
1317                 break;
1318
1319         case DHCPV6_NoAddrsAvail:
1320         case DHCPV6_NoPrefixAvail:
1321                 if (orig == DHCPV6_MSG_REQUEST)
1322                         *ret = 0; // Failure
1323                 break;
1324
1325         default:
1326                 break;
1327         }
1328 }
1329
1330
1331 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1332                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1333                 const void *status_msg, const int len,
1334                 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1335 {
1336         dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1337                 "IA_NA" : "IA_PD", status_msg, len);
1338
1339         switch (code) {
1340         case DHCPV6_NoBinding:
1341                 switch (orig) {
1342                 case DHCPV6_MSG_RENEW:
1343                 case DHCPV6_MSG_REBIND:
1344                         if ((*ret > 0) && !handled_status_codes[code])
1345                                 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1346                         break;
1347
1348                 default:
1349                         break;
1350                 }
1351                 break;
1352
1353         default:
1354                 *ret = 0;
1355                 break;
1356         }
1357 }
1358
1359 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1360 {
1361         size_t cand_len, i;
1362         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1363
1364         // Remove identical duid server candidate
1365         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1366                 if (cand->duid_len == c[i].duid_len &&
1367                                 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1368                         free(c[i].ia_na);
1369                         free(c[i].ia_pd);
1370                         odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1371                         break;
1372                 }
1373         }
1374
1375         for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1376                 i < cand_len / sizeof(*c); ++i) {
1377                 if (c[i].preference < cand->preference)
1378                         break;
1379         }
1380
1381         odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand));
1382 }
1383
1384 static void dhcpv6_clear_all_server_cand(void)
1385 {
1386         size_t cand_len, i;
1387         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1388
1389         // Server candidates need deep delete for IA_NA/IA_PD
1390         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1391                 free(c[i].ia_na);
1392                 free(c[i].ia_pd);
1393         }
1394         odhcp6c_clear_state(STATE_SERVER_CAND);
1395 }
1396
1397 int dhcpv6_promote_server_cand(void)
1398 {
1399         size_t cand_len;
1400         struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1401         uint16_t hdr[2];
1402         int ret = DHCPV6_STATELESS;
1403
1404         // Clear lingering candidate state info
1405         odhcp6c_clear_state(STATE_SERVER_ID);
1406         odhcp6c_clear_state(STATE_IA_NA);
1407         odhcp6c_clear_state(STATE_IA_PD);
1408
1409         if (!cand_len)
1410                 return -1;
1411
1412         if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1413                 na_mode = IA_MODE_NONE;
1414
1415                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1416                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1417
1418                 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1419         }
1420
1421         hdr[0] = htons(DHCPV6_OPT_SERVERID);
1422         hdr[1] = htons(cand->duid_len);
1423         odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1424         odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1425         accept_reconfig = cand->wants_reconfigure;
1426         if (cand->ia_na_len) {
1427                 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1428                 free(cand->ia_na);
1429                 if (na_mode != IA_MODE_NONE)
1430                         ret = DHCPV6_STATEFUL;
1431         }
1432         if (cand->ia_pd_len) {
1433                 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1434                 free(cand->ia_pd);
1435                 if (request_prefix)
1436                         ret = DHCPV6_STATEFUL;
1437         }
1438
1439         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1440         dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1441
1442         odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1443
1444         return ret;
1445 }