src/dhcpv6.c

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