src/dhcpv6.c

   1 /**
   2  * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
   3  * Copyright (C) 2017 Hans Dedecker <dedeckeh@gmail.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License v2 as published by
   7  * the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  */
  15
  16 #include <time.h>
  17 #include <fcntl.h>
  18 #include <errno.h>
  19 #include <inttypes.h>
  20 #include <stdlib.h>
  21 #include <signal.h>
  22 #include <limits.h>
  23 #include <resolv.h>
  24 #include <string.h>
  25 #include <unistd.h>
  26 #include <syslog.h>
  27 #include <stdbool.h>
  28 #include <ctype.h>
  29 #include <sys/time.h>
  30 #include <sys/ioctl.h>
  31 #include <sys/socket.h>
  32 #include <arpa/inet.h>
  33 #include <netinet/in.h>
  34
  35 #include <net/if.h>
  36 #include <net/ethernet.h>
  37
  38 #include "odhcp6c.h"
  39 #ifdef USE_LIBUBOX
  40 #include <libubox/md5.h>
  41 #else
  42 #include "md5.h"
  43 #endif
  44
  45
  46 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
  47                 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
  48 #define DHCPV6_CLIENT_PORT 546
  49 #define DHCPV6_SERVER_PORT 547
  50 #define DHCPV6_DUID_LLADDR 3
  51 #define DHCPV6_REQ_DELAY 1
  52
  53 #define DHCPV6_SOL_MAX_RT_MIN 60
  54 #define DHCPV6_SOL_MAX_RT_MAX 86400
  55 #define DHCPV6_INF_MAX_RT_MIN 60
  56 #define DHCPV6_INF_MAX_RT_MAX 86400
  57
  58 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
  59                 const uint8_t transaction[3], enum dhcpv6_msg type,
  60                 const struct in6_addr *daddr);
  61
  62 static int dhcpv6_parse_ia(void *opt, void *end);
  63
  64 static int dhcpv6_calc_refresh_timers(void);
  65 static void dhcpv6_handle_status_code(_unused const enum dhcpv6_msg orig,
  66                 const uint16_t code, const void *status_msg, const int len,
  67                 int *ret);
  68 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
  69                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
  70                 const void *status_msg, const int len,
  71                 bool handled_status_codes[_DHCPV6_Status_Max],
  72                 int *ret);
  73 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand);
  74 static void dhcpv6_clear_all_server_cand(void);
  75
  76 static reply_handler dhcpv6_handle_reply;
  77 static reply_handler dhcpv6_handle_advert;
  78 static reply_handler dhcpv6_handle_rebind_reply;
  79 static reply_handler dhcpv6_handle_reconfigure;
  80 static int dhcpv6_commit_advert(void);
  81
  82 // RFC 3315 - 5.5 Timeout and Delay values
  83 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
  84         [DHCPV6_MSG_UNKNOWN] = {false, 1, 120, 0, "<POLL>",
  85                         dhcpv6_handle_reconfigure, NULL},
  86         [DHCPV6_MSG_SOLICIT] = {true, 1, DHCPV6_SOL_MAX_RT, 0, "SOLICIT",
  87                         dhcpv6_handle_advert, dhcpv6_commit_advert},
  88         [DHCPV6_MSG_REQUEST] = {true, 1, DHCPV6_REQ_MAX_RT, 10, "REQUEST",
  89                         dhcpv6_handle_reply, NULL},
  90         [DHCPV6_MSG_RENEW] = {false, 10, DHCPV6_REN_MAX_RT, 0, "RENEW",
  91                         dhcpv6_handle_reply, NULL},
  92         [DHCPV6_MSG_REBIND] = {false, 10, DHCPV6_REB_MAX_RT, 0, "REBIND",
  93                         dhcpv6_handle_rebind_reply, NULL},
  94         [DHCPV6_MSG_RELEASE] = {false, 1, 0, 5, "RELEASE", NULL, NULL},
  95         [DHCPV6_MSG_DECLINE] = {false, 1, 0, 5, "DECLINE", NULL, NULL},
  96         [DHCPV6_MSG_INFO_REQ] = {true, 1, DHCPV6_INF_MAX_RT, 0, "INFOREQ",
  97                         dhcpv6_handle_reply, NULL},
  98 };
  99
 100 // Sockets
 101 static int sock = -1;
 102 static int ifindex = -1;
 103 static int64_t t1 = 0, t2 = 0, t3 = 0;
 104
 105 // IA states
 106 static int request_prefix = -1;
 107 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE;
 108 static bool accept_reconfig = false;
 109 // Server unicast address
 110 static struct in6_addr server_addr = IN6ADDR_ANY_INIT;
 111
 112 // Reconfigure key
 113 static uint8_t reconf_key[16];
 114
 115 // client options
 116 static unsigned int client_options = 0;
 117
 118 static uint32_t ntohl_unaligned(const uint8_t *data)
 119 {
 120         uint32_t buf;
 121
 122         memcpy(&buf, data, sizeof(buf));
 123         return ntohl(buf);
 124 }
 125
 126 int init_dhcpv6(const char *ifname, unsigned int options, int sol_timeout)
 127 {
 128         client_options = options;
 129         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
 130
 131         sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
 132         if (sock < 0)
 133                 return -1;
 134
 135         // Detect interface
 136         struct ifreq ifr;
 137         strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
 138         if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
 139                 return -1;
 140
 141         ifindex = ifr.ifr_ifindex;
 142
 143         // Create client DUID
 144         size_t client_id_len;
 145         odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 146         if (client_id_len == 0) {
 147                 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
 148                                 DHCPV6_DUID_LLADDR, 0, 1};
 149
 150                 if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
 151                         memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
 152
 153                 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
 154                 struct ifreq ifs[100], *ifp, *ifend;
 155                 struct ifconf ifc;
 156                 ifc.ifc_req = ifs;
 157                 ifc.ifc_len = sizeof(ifs);
 158
 159                 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
 160                                 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
 161                         // If our interface doesn't have an address...
 162                         ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
 163                         for (ifp = ifc.ifc_req; ifp < ifend &&
 164                                         !memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
 165                                 memcpy(ifr.ifr_name, ifp->ifr_name,
 166                                                 sizeof(ifr.ifr_name));
 167                                 if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
 168                                         continue;
 169
 170                                 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
 171                                                 ETHER_ADDR_LEN);
 172                         }
 173                 }
 174
 175                 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
 176         }
 177
 178         // Create ORO
 179         if (!(client_options & DHCPV6_STRICT_OPTIONS)) {
 180                 uint16_t oro[] = {
 181                         htons(DHCPV6_OPT_SIP_SERVER_D),
 182                         htons(DHCPV6_OPT_SIP_SERVER_A),
 183                         htons(DHCPV6_OPT_DNS_SERVERS),
 184                         htons(DHCPV6_OPT_DNS_DOMAIN),
 185                         htons(DHCPV6_OPT_UNICAST),
 186                         htons(DHCPV6_OPT_SNTP_SERVERS),
 187                         htons(DHCPV6_OPT_NTP_SERVER),
 188                         htons(DHCPV6_OPT_AFTR_NAME),
 189                         htons(DHCPV6_OPT_PD_EXCLUDE),
 190                         htons(DHCPV6_OPT_SOL_MAX_RT),
 191                         htons(DHCPV6_OPT_INF_MAX_RT),
 192 #ifdef EXT_CER_ID
 193                         htons(DHCPV6_OPT_CER_ID),
 194 #endif
 195                         htons(DHCPV6_OPT_S46_CONT_MAPE),
 196                         htons(DHCPV6_OPT_S46_CONT_MAPT),
 197                         htons(DHCPV6_OPT_S46_CONT_LW),
 198                 };
 199                 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
 200         }
 201
 202         // Configure IPv6-options
 203         int val = 1;
 204         setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
 205         setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
 206         setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
 207         setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
 208
 209         struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
 210                 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
 211
 212         if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
 213                 return -1;
 214
 215         return 0;
 216 }
 217
 218 enum {
 219         IOV_HDR=0,
 220         IOV_ORO,
 221         IOV_ORO_REFRESH,
 222         IOV_CL_ID,
 223         IOV_SRV_ID,
 224         IOV_VENDOR_CLASS_HDR,
 225         IOV_VENDOR_CLASS,
 226         IOV_USER_CLASS_HDR,
 227         IOV_USER_CLASS,
 228         IOV_RECONF_ACCEPT,
 229         IOV_FQDN,
 230         IOV_HDR_IA_NA,
 231         IOV_IA_NA,
 232         IOV_IA_PD,
 233         IOV_TOTAL
 234 };
 235
 236 int dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
 237 {
 238         int mode = DHCPV6_UNKNOWN;
 239
 240         na_mode = na;
 241         pd_mode = pd;
 242
 243         if (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE)
 244                 mode = DHCPV6_STATELESS;
 245         else if (na_mode == IA_MODE_FORCE || pd_mode == IA_MODE_FORCE)
 246                 mode = DHCPV6_STATEFUL;
 247
 248         return mode;
 249 }
 250
 251 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
 252 {
 253         // Build FQDN
 254         char fqdn_buf[256];
 255         gethostname(fqdn_buf, sizeof(fqdn_buf));
 256         struct {
 257                 uint16_t type;
 258                 uint16_t len;
 259                 uint8_t flags;
 260                 uint8_t data[256];
 261         } fqdn;
 262         size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
 263                         sizeof(fqdn.data), NULL, NULL);
 264         fqdn.type = htons(DHCPV6_OPT_FQDN);
 265         fqdn.len = htons(fqdn_len - 4);
 266         fqdn.flags = 0;
 267
 268         // Build Client ID
 269         size_t cl_id_len;
 270         void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
 271
 272         // Get Server ID
 273         size_t srv_id_len;
 274         void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
 275
 276         // Build IA_PDs
 277         size_t ia_pd_entries = 0, ia_pd_len = 0;
 278         uint8_t *ia_pd;
 279
 280         if (type == DHCPV6_MSG_SOLICIT) {
 281                 odhcp6c_clear_state(STATE_IA_PD);
 282                 size_t n_prefixes;
 283                 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
 284                 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
 285
 286                 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
 287
 288                 for (size_t i = 0; i < n_prefixes; i++) {
 289                         struct dhcpv6_ia_hdr hdr_ia_pd = {
 290                                 htons(DHCPV6_OPT_IA_PD),
 291                                 htons(sizeof(hdr_ia_pd) - 4 +
 292                                       sizeof(struct dhcpv6_ia_prefix) * !!request_prefixes[i].length),
 293                                 request_prefixes[i].iaid, 0, 0
 294                         };
 295                         struct dhcpv6_ia_prefix pref = {
 296                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 297                                 .len = htons(sizeof(pref) - 4),
 298                                 .prefix = request_prefixes[i].length
 299                         };
 300                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
 301                         ia_pd_len += sizeof(hdr_ia_pd);
 302                         if (request_prefixes[i].length) {
 303                                 memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
 304                                 ia_pd_len += sizeof(pref);
 305                         }
 306                 }
 307         } else {
 308                 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
 309                 ia_pd_entries /= sizeof(*e);
 310
 311                 // we're too lazy to count our distinct IAIDs,
 312                 // so just allocate maximally needed space
 313                 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
 314                                         sizeof(struct dhcpv6_ia_hdr)));
 315
 316                 for (size_t i = 0; i < ia_pd_entries; ++i) {
 317                         uint32_t iaid = e[i].iaid;
 318
 319                         // check if this is an unprocessed IAID and skip if not.
 320                         int new_iaid = 1;
 321                         for (int j = i-1; j >= 0; j--) {
 322                                 if (e[j].iaid == iaid) {
 323                                         new_iaid = 0;
 324                                         break;
 325                                 }
 326                         }
 327
 328                         if (!new_iaid)
 329                                 continue;
 330
 331                         // construct header
 332                         struct dhcpv6_ia_hdr hdr_ia_pd = {
 333                                 htons(DHCPV6_OPT_IA_PD),
 334                                 htons(sizeof(hdr_ia_pd) - 4),
 335                                 iaid, 0, 0
 336                         };
 337
 338                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
 339                         struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
 340                         ia_pd_len += sizeof(hdr_ia_pd);
 341
 342                         for (size_t j = i; j < ia_pd_entries; j++) {
 343                                 if (e[j].iaid != iaid)
 344                                         continue;
 345
 346                                 uint8_t ex_len = 0;
 347                                 if (e[j].priority > 0)
 348                                         ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
 349
 350                                 struct dhcpv6_ia_prefix p = {
 351                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 352                                         .len = htons(sizeof(p) - 4U + ex_len),
 353                                         .prefix = e[j].length,
 354                                         .addr = e[j].target
 355                                 };
 356
 357                                 if (type == DHCPV6_MSG_REQUEST) {
 358                                         p.preferred = htonl(e[j].preferred);
 359                                         p.valid = htonl(e[j].valid);
 360                                 }
 361
 362                                 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
 363                                 ia_pd_len += sizeof(p);
 364
 365                                 if (ex_len) {
 366                                         ia_pd[ia_pd_len++] = 0;
 367                                         ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
 368                                         ia_pd[ia_pd_len++] = 0;
 369                                         ia_pd[ia_pd_len++] = ex_len - 4;
 370                                         ia_pd[ia_pd_len++] = e[j].priority;
 371
 372                                         uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
 373                                         excl >>= (64 - e[j].priority);
 374                                         excl <<= 8 - ((e[j].priority - e[j].length) % 8);
 375
 376                                         for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
 377                                                 ia_pd[ia_pd_len + i] = excl & 0xff;
 378                                         ia_pd_len += ex_len - 5;
 379                                 }
 380
 381                                 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
 382                         }
 383                 }
 384         }
 385
 386         if (ia_pd_entries > 0)
 387                 request_prefix = 1;
 388
 389         // Build IA_NAs
 390         size_t ia_na_entries, ia_na_len = 0;
 391         void *ia_na = NULL;
 392         struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
 393         ia_na_entries /= sizeof(*e);
 394
 395         struct dhcpv6_ia_hdr hdr_ia_na = {
 396                 htons(DHCPV6_OPT_IA_NA),
 397                 htons(sizeof(hdr_ia_na) - 4),
 398                 htonl(1), 0, 0
 399         };
 400
 401         struct dhcpv6_ia_addr pa[ia_na_entries];
 402         for (size_t i = 0; i < ia_na_entries; ++i) {
 403                 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
 404                 pa[i].len = htons(sizeof(pa[i]) - 4U);
 405                 pa[i].addr = e[i].target;
 406
 407                 if (type == DHCPV6_MSG_REQUEST) {
 408                         pa[i].preferred = htonl(e[i].preferred);
 409                         pa[i].valid = htonl(e[i].valid);
 410                 } else {
 411                         pa[i].preferred = 0;
 412                         pa[i].valid = 0;
 413                 }
 414         }
 415
 416         ia_na = pa;
 417         ia_na_len = sizeof(pa);
 418         hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
 419
 420         // Reconfigure Accept
 421         struct {
 422                 uint16_t type;
 423                 uint16_t length;
 424         } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
 425
 426         // Request Information Refresh
 427         uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
 428
 429         // Build vendor-class option
 430         size_t vendor_class_len, user_class_len;
 431         struct dhcpv6_vendorclass *vendor_class = odhcp6c_get_state(STATE_VENDORCLASS, &vendor_class_len);
 432         void *user_class = odhcp6c_get_state(STATE_USERCLASS, &user_class_len);
 433
 434         struct {
 435                 uint16_t type;
 436                 uint16_t length;
 437         } vendor_class_hdr = {htons(DHCPV6_OPT_VENDOR_CLASS), htons(vendor_class_len)};
 438
 439         struct {
 440                 uint16_t type;
 441                 uint16_t length;
 442         } user_class_hdr = {htons(DHCPV6_OPT_USER_CLASS), htons(user_class_len)};
 443
 444         // Prepare Header
 445         size_t oro_len;
 446         void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
 447         struct {
 448                 uint8_t type;
 449                 uint8_t trid[3];
 450                 uint16_t elapsed_type;
 451                 uint16_t elapsed_len;
 452                 uint16_t elapsed_value;
 453                 uint16_t oro_type;
 454                 uint16_t oro_len;
 455         } hdr = {
 456                 type, {trid[0], trid[1], trid[2]},
 457                 htons(DHCPV6_OPT_ELAPSED), htons(2),
 458                         htons((ecs > 0xffff) ? 0xffff : ecs),
 459                 htons(DHCPV6_OPT_ORO), htons(oro_len),
 460         };
 461
 462         struct iovec iov[IOV_TOTAL] = {
 463                 [IOV_HDR] = {&hdr, sizeof(hdr)},
 464                 [IOV_ORO] = {oro, oro_len},
 465                 [IOV_ORO_REFRESH] = {&oro_refresh, 0},
 466                 [IOV_CL_ID] = {cl_id, cl_id_len},
 467                 [IOV_SRV_ID] = {srv_id, srv_id_len},
 468                 [IOV_VENDOR_CLASS_HDR] = {&vendor_class_hdr, vendor_class_len ? sizeof(vendor_class_hdr) : 0},
 469                 [IOV_VENDOR_CLASS] = {vendor_class, vendor_class_len},
 470                 [IOV_USER_CLASS_HDR] = {&user_class_hdr, user_class_len ? sizeof(user_class_hdr) : 0},
 471                 [IOV_USER_CLASS] = {user_class, user_class_len},
 472                 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
 473                 [IOV_FQDN] = {&fqdn, fqdn_len},
 474                 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
 475                 [IOV_IA_NA] = {ia_na, ia_na_len},
 476                 [IOV_IA_PD] = {ia_pd, ia_pd_len},
 477         };
 478
 479         size_t cnt = IOV_TOTAL;
 480         if (type == DHCPV6_MSG_INFO_REQ) {
 481                 cnt = 9;
 482                 iov[IOV_ORO_REFRESH].iov_len = sizeof(oro_refresh);
 483                 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
 484         } else if (!request_prefix)
 485                 cnt = 13;
 486
 487         // Disable IAs if not used
 488         if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
 489                 iov[IOV_HDR_IA_NA].iov_len = 0;
 490
 491         if (na_mode == IA_MODE_NONE)
 492                 iov[IOV_HDR_IA_NA].iov_len = 0;
 493
 494         if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
 495                         !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
 496                 iov[IOV_RECONF_ACCEPT].iov_len = 0;
 497
 498         if (!(client_options & DHCPV6_CLIENT_FQDN))
 499                 iov[IOV_FQDN].iov_len = 0;
 500
 501         struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
 502                 0, ALL_DHCPV6_RELAYS, ifindex};
 503         struct msghdr msg = {.msg_name = &srv, .msg_namelen = sizeof(srv),
 504                         .msg_iov = iov, .msg_iovlen = cnt};
 505
 506         switch (type) {
 507         case DHCPV6_MSG_REQUEST:
 508         case DHCPV6_MSG_RENEW:
 509         case DHCPV6_MSG_RELEASE:
 510         case DHCPV6_MSG_DECLINE:
 511                 if (!IN6_IS_ADDR_UNSPECIFIED(&server_addr) &&
 512                         odhcp6c_addr_in_scope(&server_addr)) {
 513                         srv.sin6_addr = server_addr;
 514                         if (!IN6_IS_ADDR_LINKLOCAL(&server_addr))
 515                                 srv.sin6_scope_id = 0;
 516                 }
 517                 break;
 518         default:
 519                 break;
 520         }
 521
 522         if (sendmsg(sock, &msg, 0) < 0) {
 523                 char in6_str[INET6_ADDRSTRLEN];
 524
 525                 syslog(LOG_ERR, "Failed to send DHCPV6 message to %s (%s)",
 526                         inet_ntop(AF_INET6, (const void *)&srv.sin6_addr,
 527                                 in6_str, sizeof(in6_str)), strerror(errno));
 528         }
 529 }
 530
 531 static int64_t dhcpv6_rand_delay(int64_t time)
 532 {
 533         int random;
 534         odhcp6c_random(&random, sizeof(random));
 535
 536         return (time * ((int64_t)random % 1000LL)) / 10000LL;
 537 }
 538
 539 int dhcpv6_request(enum dhcpv6_msg type)
 540 {
 541         uint8_t rc = 0;
 542         uint64_t timeout = UINT32_MAX;
 543         struct dhcpv6_retx *retx = &dhcpv6_retx[type];
 544
 545         if (retx->delay) {
 546                 struct timespec ts = {0, 0};
 547                 ts.tv_nsec = (dhcpv6_rand_delay((10000 * DHCPV6_REQ_DELAY) / 2) + (1000 * DHCPV6_REQ_DELAY) / 2) * 1000000;
 548
 549                 while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
 550         }
 551
 552         if (type == DHCPV6_MSG_UNKNOWN)
 553                 timeout = t1;
 554         else if (type == DHCPV6_MSG_RENEW)
 555                 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
 556         else if (type == DHCPV6_MSG_REBIND)
 557                 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
 558
 559         if (timeout == 0)
 560                 return -1;
 561
 562         syslog(LOG_NOTICE, "Starting %s transaction (timeout %"PRIu64"s, max rc %d)",
 563                         retx->name, timeout, retx->max_rc);
 564
 565         uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
 566
 567         // Generate transaction ID
 568         uint8_t trid[3] = {0, 0, 0};
 569         if (type != DHCPV6_MSG_UNKNOWN)
 570                 odhcp6c_random(trid, sizeof(trid));
 571
 572         ssize_t len = -1;
 573         int64_t rto = 0;
 574
 575         do {
 576                 if (rto == 0) {
 577                         int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 578
 579                         // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
 580                         while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
 581                                 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 582
 583                         rto = (retx->init_timeo * 1000 + delay);
 584                 } else
 585                         rto = (2 * rto + dhcpv6_rand_delay(rto));
 586
 587                 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
 588                         rto = retx->max_timeo * 1000 +
 589                                 dhcpv6_rand_delay(retx->max_timeo * 1000);
 590
 591                 // Calculate end for this round and elapsed time
 592                 uint64_t round_end = round_start + rto;
 593                 elapsed = round_start - start;
 594
 595                 // Don't wait too long if timeout differs from infinite
 596                 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
 597                         round_end = timeout * 1000 + start;
 598
 599                 // Built and send package
 600                 switch (type) {
 601                 case DHCPV6_MSG_UNKNOWN:
 602                         break;
 603                 default:
 604                         syslog(LOG_NOTICE, "Send %s message (elapsed %"PRIu64"ms, rc %d)",
 605                                         retx->name, elapsed, rc);
 606                         // Fall through
 607                 case DHCPV6_MSG_SOLICIT:
 608                 case DHCPV6_MSG_INFO_REQ:
 609                         dhcpv6_send(type, trid, elapsed / 10);
 610                         rc++;
 611                 }
 612
 613                 // Receive rounds
 614                 for (; len < 0 && (round_start < round_end);
 615                                 round_start = odhcp6c_get_milli_time()) {
 616                         uint8_t buf[1536];
 617                         union {
 618                                 struct cmsghdr hdr;
 619                                 uint8_t buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
 620                         } cmsg_buf;
 621                         struct iovec iov = {buf, sizeof(buf)};
 622                         struct sockaddr_in6 addr;
 623                         struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr),
 624                                         .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf.buf,
 625                                         .msg_controllen = sizeof(cmsg_buf)};
 626                         struct in6_pktinfo *pktinfo = NULL;
 627
 628                         // Check for pending signal
 629                         if (odhcp6c_signal_process())
 630                                 return -1;
 631
 632                         // Set timeout for receiving
 633                         uint64_t t = round_end - round_start;
 634                         struct timeval tv = {t / 1000, (t % 1000) * 1000};
 635                         setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
 636                                         &tv, sizeof(tv));
 637
 638                         // Receive cycle
 639                         len = recvmsg(sock, &msg, 0);
 640                         if (len < 0)
 641                                 continue;
 642
 643                         for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
 644                                 ch = CMSG_NXTHDR(&msg, ch)) {
 645                                 if (ch->cmsg_level == SOL_IPV6 &&
 646                                         ch->cmsg_type == IPV6_PKTINFO) {
 647                                         pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
 648                                         break;
 649                                 }
 650                         }
 651
 652                         if (pktinfo == NULL) {
 653                                 len = -1;
 654                                 continue;
 655                         }
 656
 657                         if (!dhcpv6_response_is_valid(buf, len, trid,
 658                                                         type, &pktinfo->ipi6_addr)) {
 659                                 len = -1;
 660                                 continue;
 661                         }
 662
 663                         uint8_t *opt = &buf[4];
 664                         uint8_t *opt_end = opt + len - 4;
 665
 666                         round_start = odhcp6c_get_milli_time();
 667                         elapsed = round_start - start;
 668                         syslog(LOG_NOTICE, "Got a valid reply after %"PRIu64"ms",
 669                                         elapsed);
 670
 671                         if (retx->handler_reply)
 672                                 len = retx->handler_reply(type, rc, opt, opt_end, &addr);
 673
 674                         if (len > 0 && round_end - round_start > 1000)
 675                                 round_end = 1000 + round_start;
 676                 }
 677
 678                 // Allow
 679                 if (retx->handler_finish)
 680                         len = retx->handler_finish();
 681         } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
 682                         (!retx->max_rc || rc < retx->max_rc));
 683         return len;
 684 }
 685
 686 // Message validation checks according to RFC3315 chapter 15
 687 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
 688                 const uint8_t transaction[3], enum dhcpv6_msg type,
 689                 const struct in6_addr *daddr)
 690 {
 691         const struct dhcpv6_header *rep = buf;
 692         if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
 693                         transaction, sizeof(rep->tr_id)))
 694                 return false; // Invalid reply
 695
 696         if (type == DHCPV6_MSG_SOLICIT) {
 697                 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
 698                                 rep->msg_type != DHCPV6_MSG_REPLY)
 699                         return false;
 700
 701         } else if (type == DHCPV6_MSG_UNKNOWN) {
 702                 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
 703                         return false;
 704
 705         } else if (rep->msg_type != DHCPV6_MSG_REPLY)
 706                 return false;
 707
 708         uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
 709                 rcmsg = DHCPV6_MSG_UNKNOWN;
 710         uint16_t otype, olen = UINT16_MAX;
 711         bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
 712                 ia_present = false, options_valid = true;
 713
 714         size_t client_id_len, server_id_len;
 715         void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 716         void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 717
 718         dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
 719                 if (otype == DHCPV6_OPT_CLIENTID) {
 720                         clientid_ok = (olen + 4U == client_id_len) && !memcmp(
 721                                         &odata[-4], client_id, client_id_len);
 722                 } else if (otype == DHCPV6_OPT_SERVERID) {
 723                         if (server_id_len)
 724                                 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
 725                                                 &odata[-4], server_id, server_id_len);
 726                         else
 727                                 serverid_ok = true;
 728                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
 729                                 sizeof(struct dhcpv6_auth_reconfigure)) {
 730                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
 731                         if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
 732                                 continue;
 733
 734                         md5_ctx_t md5;
 735                         uint8_t serverhash[16], secretbytes[64];
 736                         uint32_t hash[4];
 737                         memcpy(serverhash, r->key, sizeof(serverhash));
 738                         memset(r->key, 0, sizeof(r->key));
 739
 740                         memset(secretbytes, 0, sizeof(secretbytes));
 741                         memcpy(secretbytes, reconf_key, sizeof(reconf_key));
 742
 743                         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 744                                 secretbytes[i] ^= 0x36;
 745
 746                         md5_begin(&md5);
 747                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 748                         md5_hash(buf, len, &md5);
 749                         md5_end(hash, &md5);
 750
 751                         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 752                                 secretbytes[i] ^= 0x36;
 753                                 secretbytes[i] ^= 0x5c;
 754                         }
 755
 756                         md5_begin(&md5);
 757                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 758                         md5_hash(hash, 16, &md5);
 759                         md5_end(hash, &md5);
 760
 761                         rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
 762                 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
 763                         rcmsg = odata[0];
 764                 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
 765                         ia_present = true;
 766                         if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
 767                                 options_valid = false;
 768                 } else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
 769                                 (otype == DHCPV6_OPT_PD_EXCLUDE))
 770                         // Options are not allowed on global level
 771                         options_valid = false;
 772         }
 773
 774         if (!options_valid || ((odata + olen) > end))
 775                 return false;
 776
 777         if (type == DHCPV6_MSG_INFO_REQ && ia_present)
 778                 return false;
 779
 780         if (rep->msg_type == DHCPV6_MSG_RECONF) {
 781                 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
 782                         (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
 783                         !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
 784                         return false;
 785         }
 786
 787         return clientid_ok && serverid_ok;
 788 }
 789
 790 int dhcpv6_poll_reconfigure(void)
 791 {
 792         int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
 793
 794         if (ret != -1)
 795                 ret = dhcpv6_request(ret);
 796
 797         return ret;
 798 }
 799
 800 static int dhcpv6_handle_reconfigure(enum dhcpv6_msg orig, const int rc,
 801                 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
 802 {
 803         uint16_t otype, olen;
 804         uint8_t *odata;
 805         int msg = -1;
 806
 807         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 808                 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
 809                         switch (odata[0]) {
 810                         case DHCPV6_MSG_RENEW:
 811                                 if (t1 != UINT32_MAX)
 812                                         t1 = 0;
 813                         // Fall through
 814                         case DHCPV6_MSG_INFO_REQ:
 815                                 msg = odata[0];
 816                                 break;
 817
 818                         default:
 819                                 break;
 820                         }
 821                 }
 822         }
 823
 824         dhcpv6_handle_reply(orig, rc, NULL, NULL, NULL);
 825
 826         return msg;
 827 }
 828
 829 // Collect all advertised servers
 830 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
 831                 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
 832 {
 833         uint16_t olen, otype;
 834         uint8_t *odata, pref = 0;
 835         struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
 836                                         IN6ADDR_ANY_INIT, DHCPV6_SOL_MAX_RT,
 837                                         DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
 838         bool have_na = false;
 839         int have_pd = 0;
 840
 841         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 842                 if (orig == DHCPV6_MSG_SOLICIT &&
 843                                 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
 844                                 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
 845                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 846                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 847                 }
 848
 849                 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
 850                         memcpy(cand.duid, odata, olen);
 851                         cand.duid_len = olen;
 852                 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
 853                                 cand.preference >= 0) {
 854                         cand.preference = pref = odata[0];
 855                 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(cand.server_addr)) {
 856                         cand.server_addr = *(struct in6_addr *)odata;
 857                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 858                         cand.wants_reconfigure = true;
 859                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
 860                         uint32_t sol_max_rt = ntohl_unaligned(odata);
 861                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
 862                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
 863                                 cand.sol_max_rt = sol_max_rt;
 864
 865                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
 866                         uint32_t inf_max_rt = ntohl_unaligned(odata);
 867                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
 868                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
 869                                 cand.inf_max_rt = inf_max_rt;
 870
 871                 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix &&
 872                                         olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
 873                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 874                         uint8_t *oend = odata + olen, *d;
 875                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
 876                                 if (otype == DHCPV6_OPT_IA_PREFIX &&
 877                                                 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
 878                                         struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
 879                                         have_pd = p->prefix;
 880                                 }
 881                         }
 882                 } else if (otype == DHCPV6_OPT_IA_NA &&
 883                                         olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
 884                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 885                         uint8_t *oend = odata + olen, *d;
 886
 887                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
 888                                 if (otype == DHCPV6_OPT_IA_ADDR &&
 889                                                 olen >= -4 + sizeof(struct dhcpv6_ia_addr))
 890                                         have_na = true;
 891                         }
 892                 }
 893         }
 894
 895         if ((!have_na && na_mode == IA_MODE_FORCE) ||
 896                         (!have_pd && pd_mode == IA_MODE_FORCE)) {
 897                 /*
 898                  * RFC7083 states to process the SOL_MAX_RT and
 899                  * INF_MAX_RT options even if the DHCPv6 server
 900                  * did not propose any IA_NA and/or IA_PD
 901                  */
 902                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
 903                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
 904                 return -1;
 905         }
 906
 907         if (na_mode != IA_MODE_NONE && !have_na) {
 908                 cand.has_noaddravail = true;
 909                 cand.preference -= 1000;
 910         }
 911
 912         if (pd_mode != IA_MODE_NONE) {
 913                 if (have_pd)
 914                         cand.preference += 2000 + (128 - have_pd);
 915                 else
 916                         cand.preference -= 2000;
 917         }
 918
 919         if (cand.duid_len > 0) {
 920                 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
 921                 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
 922                 dhcpv6_add_server_cand(&cand);
 923         }
 924
 925         return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
 926 }
 927
 928 static int dhcpv6_commit_advert(void)
 929 {
 930         return dhcpv6_promote_server_cand();
 931 }
 932
 933 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
 934                 const void *opt, const void *end, const struct sockaddr_in6 *from)
 935 {
 936         dhcpv6_handle_advert(orig, rc, opt, end, from);
 937         if (dhcpv6_commit_advert() < 0)
 938                 return -1;
 939
 940         return dhcpv6_handle_reply(orig, rc, opt, end, from);
 941 }
 942
 943 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
 944                 const void *opt, const void *end, const struct sockaddr_in6 *from)
 945 {
 946         uint8_t *odata;
 947         uint16_t otype, olen;
 948         uint32_t refresh = 86400;
 949         int ret = 1;
 950         bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
 951
 952         odhcp6c_expire();
 953
 954         if (orig == DHCPV6_MSG_UNKNOWN) {
 955                 static time_t last_update = 0;
 956                 time_t now = odhcp6c_get_milli_time() / 1000;
 957
 958                 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 959                 last_update = now;
 960
 961                 if (t1 != UINT32_MAX)
 962                         t1 -= elapsed;
 963
 964                 if (t2 != UINT32_MAX)
 965                         t2 -= elapsed;
 966
 967                 if (t3 != UINT32_MAX)
 968                         t3 -= elapsed;
 969
 970                 if (t1 < 0)
 971                         t1 = 0;
 972
 973                 if (t2 < 0)
 974                         t2 = 0;
 975
 976                 if (t3 < 0)
 977                         t3 = 0;
 978         }
 979
 980         if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
 981                 // Delete NA and PD we have in the state from the Advert
 982                 odhcp6c_clear_state(STATE_IA_NA);
 983                 odhcp6c_clear_state(STATE_IA_PD);
 984         }
 985
 986         if (opt) {
 987                 odhcp6c_clear_state(STATE_DNS);
 988                 odhcp6c_clear_state(STATE_SEARCH);
 989                 odhcp6c_clear_state(STATE_SNTP_IP);
 990                 odhcp6c_clear_state(STATE_NTP_IP);
 991                 odhcp6c_clear_state(STATE_NTP_FQDN);
 992                 odhcp6c_clear_state(STATE_SIP_IP);
 993                 odhcp6c_clear_state(STATE_SIP_FQDN);
 994                 odhcp6c_clear_state(STATE_AFTR_NAME);
 995                 odhcp6c_clear_state(STATE_CER);
 996                 odhcp6c_clear_state(STATE_S46_MAPT);
 997                 odhcp6c_clear_state(STATE_S46_MAPE);
 998                 odhcp6c_clear_state(STATE_S46_LW);
 999                 odhcp6c_clear_state(STATE_PASSTHRU);
1000                 odhcp6c_clear_state(STATE_CUSTOM_OPTS);
1001
1002                 // Parse and find all matching IAs
1003                 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
1004                         bool passthru = true;
1005
1006                         if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
1007                                         && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
1008                                 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
1009
1010                                 if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) ||
1011                                         (pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD))
1012                                         continue;
1013
1014                                 // Test ID
1015                                 if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
1016                                         continue;
1017
1018                                 uint16_t code = DHCPV6_Success;
1019                                 uint16_t stype, slen;
1020                                 uint8_t *sdata;
1021                                 // Get and handle status code
1022                                 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
1023                                                 stype, slen, sdata) {
1024                                         if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
1025                                                 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
1026                                                 uint16_t mlen = (slen > 2) ? slen - 2 : 0;
1027
1028                                                 code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
1029
1030                                                 if (code == DHCPV6_Success)
1031                                                         continue;
1032
1033                                                 dhcpv6_handle_ia_status_code(orig, ia_hdr,
1034                                                         code, mdata, mlen, handled_status_codes, &ret);
1035
1036                                                 if (ret > 0)
1037                                                         return ret;
1038
1039                                                 break;
1040                                         }
1041                                 }
1042
1043                                 if (code != DHCPV6_Success)
1044                                         continue;
1045
1046                                 dhcpv6_parse_ia(ia_hdr, odata + olen);
1047                                 passthru = false;
1048                         } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(server_addr)) {
1049                                 server_addr = *(struct in6_addr *)odata;
1050                                 passthru = false;
1051                         } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
1052                                 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
1053                                 uint16_t mlen = (olen > 2) ? olen - 2 : 0;
1054                                 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
1055
1056                                 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
1057                                 passthru = false;
1058                         } else if (otype == DHCPV6_OPT_DNS_SERVERS) {
1059                                 if (olen % 16 == 0)
1060                                         odhcp6c_add_state(STATE_DNS, odata, olen);
1061                         } else if (otype == DHCPV6_OPT_DNS_DOMAIN)
1062                                 odhcp6c_add_state(STATE_SEARCH, odata, olen);
1063                         else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
1064                                 if (olen % 16 == 0)
1065                                         odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
1066                         } else if (otype == DHCPV6_OPT_NTP_SERVER) {
1067                                 uint16_t stype, slen;
1068                                 uint8_t *sdata;
1069                                 // Test status and bail if error
1070                                 dhcpv6_for_each_option(odata, odata + olen,
1071                                                 stype, slen, sdata) {
1072                                         if (slen == 16 && (stype == NTP_MC_ADDR ||
1073                                                         stype == NTP_SRV_ADDR))
1074                                                 odhcp6c_add_state(STATE_NTP_IP,
1075                                                                 sdata, slen);
1076                                         else if (slen > 0 && stype == NTP_SRV_FQDN)
1077                                                 odhcp6c_add_state(STATE_NTP_FQDN,
1078                                                                 sdata, slen);
1079                                 }
1080                         } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1081                                 if (olen == 16)
1082                                         odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1083                         } else if (otype == DHCPV6_OPT_SIP_SERVER_D)
1084                                 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1085                         else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1086                                 refresh = ntohl_unaligned(odata);
1087                                 passthru = false;
1088                         } else if (otype == DHCPV6_OPT_AUTH) {
1089                                 if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1090                                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1091                                         if (r->protocol == 3 && r->algorithm == 1 &&
1092                                                         r->reconf_type == 1)
1093                                                 memcpy(reconf_key, r->key, sizeof(r->key));
1094                                 }
1095                                 passthru = false;
1096                         } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1097                                 size_t cur_len;
1098                                 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1099                                 if (cur_len == 0)
1100                                         odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1101                                 passthru = false;
1102                         } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1103                                 uint32_t sol_max_rt = ntohl_unaligned(odata);
1104                                 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1105                                                 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1106                                         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1107                                 passthru = false;
1108                         } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1109                                 uint32_t inf_max_rt = ntohl_unaligned(odata);
1110                                 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1111                                                 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1112                                         dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1113                                 passthru = false;
1114         #ifdef EXT_CER_ID
1115                         } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1116                                         sizeof(struct dhcpv6_cer_id)) {
1117                                 struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1118                                 struct in6_addr any = IN6ADDR_ANY_INIT;
1119                                 if (memcmp(&cer_id->addr, &any, sizeof(any)))
1120                                         odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1121                                 passthru = false;
1122         #endif
1123                         } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1124                                 odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1125                                 passthru = false;
1126                         } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1127                                 size_t mape_len;
1128                                 odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1129                                 if (mape_len == 0)
1130                                         odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1131                                 passthru = false;
1132                         } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1133                                 odhcp6c_add_state(STATE_S46_LW, odata, olen);
1134                                 passthru = false;
1135                         } else if (otype == DHCPV6_OPT_CLIENTID ||
1136                                         otype == DHCPV6_OPT_SERVERID ||
1137                                         otype == DHCPV6_OPT_IA_TA ||
1138                                         otype == DHCPV6_OPT_PREF ||
1139                                         otype == DHCPV6_OPT_UNICAST ||
1140                                         otype == DHCPV6_OPT_FQDN ||
1141                                         otype == DHCPV6_OPT_RECONF_ACCEPT)
1142                                 passthru = false;
1143                         else
1144                                 odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1145
1146                         if (passthru)
1147                                 odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1148                 }
1149         }
1150
1151         switch (orig) {
1152         case DHCPV6_MSG_REQUEST:
1153         case DHCPV6_MSG_REBIND:
1154         case DHCPV6_MSG_RENEW:
1155                 // Update refresh timers if no fatal status code was received
1156                 if ((ret > 0) && (ret = dhcpv6_calc_refresh_timers())) {
1157                         if (orig == DHCPV6_MSG_REQUEST) {
1158                                 // All server candidates can be cleared if not yet bound
1159                                 if (!odhcp6c_is_bound())
1160                                         dhcpv6_clear_all_server_cand();
1161
1162                                 odhcp6c_clear_state(STATE_SERVER_ADDR);
1163                                 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1164                         } else if (orig == DHCPV6_MSG_RENEW) {
1165                                 // Send further renews if T1 is not set
1166                                 if (!t1)
1167                                         ret = -1;
1168
1169                         } else if (orig == DHCPV6_MSG_REBIND) {
1170                                 // Send further rebinds if T1 and T2 is not set
1171                                 if (!t1 && !t2)
1172                                         ret = -1;
1173
1174                                 odhcp6c_clear_state(STATE_SERVER_ADDR);
1175                                 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1176                         }
1177                 }
1178                 break;
1179
1180         case DHCPV6_MSG_INFO_REQ:
1181                 if (ret > 0) {
1182                         // All server candidates can be cleared if not yet bound
1183                         if (!odhcp6c_is_bound())
1184                                 dhcpv6_clear_all_server_cand();
1185
1186                         t1 = refresh;
1187                 }
1188                 break;
1189
1190         default:
1191                 break;
1192         }
1193
1194         return ret;
1195 }
1196
1197 static int dhcpv6_parse_ia(void *opt, void *end)
1198 {
1199         struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1200         int parsed_ia = 0;
1201         uint32_t t1, t2;
1202         uint16_t otype, olen;
1203         uint8_t *odata;
1204
1205         t1 = ntohl(ia_hdr->t1);
1206         t2 = ntohl(ia_hdr->t2);
1207
1208         if (t1 > t2)
1209                 return 0;
1210
1211         // Update address IA
1212         dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1213                 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0, 0,
1214                                 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0};
1215
1216                 entry.iaid = ia_hdr->iaid;
1217
1218                 if (otype == DHCPV6_OPT_IA_PREFIX) {
1219                         struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1220                         if (olen + 4U < sizeof(*prefix))
1221                                 continue;
1222
1223                         entry.valid = ntohl(prefix->valid);
1224                         entry.preferred = ntohl(prefix->preferred);
1225
1226                         if (entry.preferred > entry.valid)
1227                                 continue;
1228
1229                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1230                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1231                         if (entry.t1 > entry.t2)
1232                                 entry.t1 = entry.t2;
1233
1234                         entry.length = prefix->prefix;
1235                         entry.target = prefix->addr;
1236                         uint16_t stype, slen;
1237                         uint8_t *sdata;
1238
1239                         // Parse PD-exclude
1240                         bool ok = true;
1241                         dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1242                                         odata + olen, stype, slen, sdata) {
1243                                 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1244                                         continue;
1245
1246                                 uint8_t elen = sdata[0];
1247                                 if (elen > 64)
1248                                         elen = 64;
1249
1250                                 if (entry.length < 32 || elen <= entry.length) {
1251                                         ok = false;
1252                                         continue;
1253                                 }
1254
1255                                 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1256                                 if (slen <= bytes) {
1257                                         ok = false;
1258                                         continue;
1259                                 }
1260
1261                                 uint32_t exclude = 0;
1262                                 do {
1263                                         exclude = exclude << 8 | sdata[bytes];
1264                                 } while (--bytes);
1265
1266                                 exclude >>= 8 - ((elen - entry.length) % 8);
1267                                 exclude <<= 64 - elen;
1268
1269                                 // Abusing router & priority fields for exclusion
1270                                 entry.router = entry.target;
1271                                 entry.router.s6_addr32[1] |= htonl(exclude);
1272                                 entry.priority = elen;
1273                         }
1274
1275                         if (ok) {
1276                                 odhcp6c_update_entry(STATE_IA_PD, &entry, 0, false);
1277                                 parsed_ia++;
1278                         }
1279
1280                         entry.priority = 0;
1281                         memset(&entry.router, 0, sizeof(entry.router));
1282                 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1283                         struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1284                         if (olen + 4U < sizeof(*addr))
1285                                 continue;
1286
1287                         entry.preferred = ntohl(addr->preferred);
1288                         entry.valid = ntohl(addr->valid);
1289
1290                         if (entry.preferred > entry.valid)
1291                                 continue;
1292
1293                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1294                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1295                         if (entry.t1 > entry.t2)
1296                                 entry.t1 = entry.t2;
1297
1298                         entry.length = 128;
1299                         entry.target = addr->addr;
1300
1301                         odhcp6c_update_entry(STATE_IA_NA, &entry, 0, false);
1302                         parsed_ia++;
1303                 }
1304         }
1305         return parsed_ia;
1306 }
1307
1308 static int dhcpv6_calc_refresh_timers(void)
1309 {
1310         struct odhcp6c_entry *e;
1311         size_t ia_na_entries, ia_pd_entries, i;
1312         int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1313
1314         e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1315         ia_na_entries /= sizeof(*e);
1316
1317         for (i = 0; i < ia_na_entries; i++) {
1318                 if (e[i].t1 < l_t1)
1319                         l_t1 = e[i].t1;
1320
1321                 if (e[i].t2 < l_t2)
1322                         l_t2 = e[i].t2;
1323
1324                 if (e[i].valid > l_t3)
1325                         l_t3 = e[i].valid;
1326         }
1327
1328         e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1329         ia_pd_entries /= sizeof(*e);
1330
1331         for (i = 0; i < ia_pd_entries; i++) {
1332                 if (e[i].t1 < l_t1)
1333                         l_t1 = e[i].t1;
1334
1335                 if (e[i].t2 < l_t2)
1336                         l_t2 = e[i].t2;
1337
1338                 if (e[i].valid > l_t3)
1339                         l_t3 = e[i].valid;
1340         }
1341
1342         if (ia_pd_entries || ia_na_entries) {
1343                 t1 = l_t1;
1344                 t2 = l_t2;
1345                 t3 = l_t3;
1346         }
1347
1348         return (int)(ia_pd_entries + ia_na_entries);
1349 }
1350
1351 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1352                 const void *status_msg, int len)
1353 {
1354         const char *src = status_msg;
1355         char buf[len + 3];
1356         char *dst = buf;
1357
1358         if (len) {
1359                 *dst++ = '(';
1360                 while (len--) {
1361                         *dst = isprint((unsigned char)*src) ? *src : '?';
1362                         src++;
1363                         dst++;
1364                 }
1365                 *dst++ = ')';
1366         }
1367
1368         *dst = 0;
1369
1370         syslog(LOG_WARNING, "Server returned %s status %i %s",
1371                 scope, code, buf);
1372 }
1373
1374 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1375                 const uint16_t code, const void *status_msg, const int len,
1376                 int *ret)
1377 {
1378         dhcpv6_log_status_code(code, "message", status_msg, len);
1379
1380         switch (code) {
1381         case DHCPV6_UnspecFail:
1382                 // Generic failure
1383                 *ret = 0;
1384                 break;
1385
1386         case DHCPV6_UseMulticast:
1387                 switch(orig) {
1388                 case DHCPV6_MSG_REQUEST:
1389                 case DHCPV6_MSG_RENEW:
1390                 case DHCPV6_MSG_RELEASE:
1391                 case DHCPV6_MSG_DECLINE:
1392                         // Message needs to be retransmitted according to RFC3315 chapter 18.1.8
1393                         server_addr = in6addr_any;
1394                         *ret = 0;
1395                         break;
1396                 default:
1397                         break;
1398                 }
1399                 break;
1400
1401         case DHCPV6_NoAddrsAvail:
1402         case DHCPV6_NoPrefixAvail:
1403                 if (orig == DHCPV6_MSG_REQUEST)
1404                         *ret = 0; // Failure
1405                 break;
1406
1407         default:
1408                 break;
1409         }
1410 }
1411
1412 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1413                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1414                 const void *status_msg, const int len,
1415                 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1416 {
1417         dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1418                 "IA_NA" : "IA_PD", status_msg, len);
1419
1420         switch (code) {
1421         case DHCPV6_NoBinding:
1422                 switch (orig) {
1423                 case DHCPV6_MSG_RENEW:
1424                 case DHCPV6_MSG_REBIND:
1425                         if ((*ret > 0) && !handled_status_codes[code])
1426                                 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1427                         break;
1428
1429                 default:
1430                         break;
1431                 }
1432                 break;
1433
1434         default:
1435                 *ret = 0;
1436                 break;
1437         }
1438 }
1439
1440 // Note this always takes ownership of cand->ia_na and cand->ia_pd
1441 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1442 {
1443         size_t cand_len, i;
1444         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1445
1446         // Remove identical duid server candidate
1447         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1448                 if (cand->duid_len == c[i].duid_len &&
1449                                 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1450                         free(c[i].ia_na);
1451                         free(c[i].ia_pd);
1452                         odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1453                         break;
1454                 }
1455         }
1456
1457         for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1458                 i < cand_len / sizeof(*c); ++i) {
1459                 if (c[i].preference < cand->preference)
1460                         break;
1461         }
1462
1463         if (odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand))) {
1464                 free(cand->ia_na);
1465                 free(cand->ia_pd);
1466         }
1467 }
1468
1469 static void dhcpv6_clear_all_server_cand(void)
1470 {
1471         size_t cand_len, i;
1472         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1473
1474         // Server candidates need deep delete for IA_NA/IA_PD
1475         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1476                 free(c[i].ia_na);
1477                 free(c[i].ia_pd);
1478         }
1479         odhcp6c_clear_state(STATE_SERVER_CAND);
1480 }
1481
1482 int dhcpv6_promote_server_cand(void)
1483 {
1484         size_t cand_len;
1485         struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1486         uint16_t hdr[2];
1487         int ret = DHCPV6_STATELESS;
1488
1489         // Clear lingering candidate state info
1490         odhcp6c_clear_state(STATE_SERVER_ID);
1491         odhcp6c_clear_state(STATE_IA_NA);
1492         odhcp6c_clear_state(STATE_IA_PD);
1493
1494         if (!cand_len)
1495                 return -1;
1496
1497         if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1498                 na_mode = IA_MODE_NONE;
1499
1500                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1501                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1502
1503                 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1504         }
1505
1506         hdr[0] = htons(DHCPV6_OPT_SERVERID);
1507         hdr[1] = htons(cand->duid_len);
1508         odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1509         odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1510         accept_reconfig = cand->wants_reconfigure;
1511
1512         if (cand->ia_na_len) {
1513                 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1514                 free(cand->ia_na);
1515                 if (na_mode != IA_MODE_NONE)
1516                         ret = DHCPV6_STATEFUL;
1517         }
1518
1519         if (cand->ia_pd_len) {
1520                 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1521                 free(cand->ia_pd);
1522                 if (request_prefix)
1523                         ret = DHCPV6_STATEFUL;
1524         }
1525
1526         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1527         dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1528
1529         odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1530
1531         return ret;
1532 }