src/dhcpv6.c

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