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