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