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