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];
 706                         uint32_t hash[4];
 707                         memcpy(serverhash, r->key, sizeof(serverhash));
 708                         memset(r->key, 0, sizeof(r->key));
 709
 710                         memset(secretbytes, 0, sizeof(secretbytes));
 711                         memcpy(secretbytes, reconf_key, sizeof(reconf_key));
 712
 713                         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 714                                 secretbytes[i] ^= 0x36;
 715
 716                         md5_begin(&md5);
 717                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 718                         md5_hash(buf, len, &md5);
 719                         md5_end(hash, &md5);
 720
 721                         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 722                                 secretbytes[i] ^= 0x36;
 723                                 secretbytes[i] ^= 0x5c;
 724                         }
 725
 726                         md5_begin(&md5);
 727                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 728                         md5_hash(hash, 16, &md5);
 729                         md5_end(hash, &md5);
 730
 731                         rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
 732                 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
 733                         rcmsg = odata[0];
 734                 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
 735                         ia_present = true;
 736                         if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
 737                                 options_valid = false;
 738                 }
 739                 else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
 740                                 (otype == DHCPV6_OPT_PD_EXCLUDE)) {
 741                         // Options are not allowed on global level
 742                         options_valid = false;
 743                 }
 744         }
 745
 746         if (!options_valid || ((odata + olen) > end))
 747                 return false;
 748
 749         if (type == DHCPV6_MSG_INFO_REQ && ia_present)
 750                 return false;
 751
 752         if (rep->msg_type == DHCPV6_MSG_RECONF) {
 753                 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
 754                         (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
 755                         !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
 756                         return false;
 757         }
 758
 759         return clientid_ok && serverid_ok;
 760 }
 761
 762
 763 int dhcpv6_poll_reconfigure(void)
 764 {
 765         int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
 766         if (ret != -1)
 767                 ret = dhcpv6_request(ret);
 768
 769         return ret;
 770 }
 771
 772
 773 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
 774                 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
 775 {
 776         uint16_t otype, olen;
 777         uint8_t *odata, msg = DHCPV6_MSG_RENEW;
 778         dhcpv6_for_each_option(opt, end, otype, olen, odata)
 779                 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
 780                                 odata[0] == DHCPV6_MSG_RENEW ||
 781                                 odata[0] == DHCPV6_MSG_INFO_REQ))
 782                         msg = odata[0];
 783
 784         dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL, NULL);
 785         return msg;
 786 }
 787
 788
 789 // Collect all advertised servers
 790 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
 791                 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
 792 {
 793         uint16_t olen, otype;
 794         uint8_t *odata, pref = 0;
 795         struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
 796                                         DHCPV6_SOL_MAX_RT,
 797                                         DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
 798         bool have_na = false;
 799         int have_pd = 0;
 800
 801         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 802                 if (orig == DHCPV6_MSG_SOLICIT &&
 803                                 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
 804                                 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
 805                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 806                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 807                 }
 808
 809                 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
 810                         memcpy(cand.duid, odata, olen);
 811                         cand.duid_len = olen;
 812                 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
 813                                 cand.preference >= 0) {
 814                         cand.preference = pref = odata[0];
 815                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 816                         cand.wants_reconfigure = true;
 817                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
 818                         uint32_t sol_max_rt = ntohl_unaligned(odata);
 819                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
 820                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
 821                                 cand.sol_max_rt = sol_max_rt;
 822                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
 823                         uint32_t inf_max_rt = ntohl_unaligned(odata);
 824                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
 825                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
 826                                 cand.inf_max_rt = inf_max_rt;
 827                 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix &&
 828                                         olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
 829                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 830                         uint8_t *oend = odata + olen, *d;
 831                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
 832                                 if (otype == DHCPV6_OPT_IA_PREFIX &&
 833                                                 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
 834                                         struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
 835                                         have_pd = p->prefix;
 836                                 }
 837                         }
 838                 } else if (otype == DHCPV6_OPT_IA_NA &&
 839                                         olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
 840                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 841                         uint8_t *oend = odata + olen, *d;
 842                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
 843                                 if (otype == DHCPV6_OPT_IA_ADDR &&
 844                                                 olen >= -4 + sizeof(struct dhcpv6_ia_addr))
 845                                         have_na = true;
 846                 }
 847         }
 848
 849         if ((!have_na && na_mode == IA_MODE_FORCE) ||
 850                         (!have_pd && pd_mode == IA_MODE_FORCE)) {
 851                 /*
 852                  * RFC7083 states to process the SOL_MAX_RT and
 853                  * INF_MAX_RT options even if the DHCPv6 server
 854                  * did not propose any IA_NA and/or IA_PD
 855                  */
 856                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
 857                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
 858                 return -1;
 859         }
 860
 861         if (na_mode != IA_MODE_NONE && !have_na) {
 862                 cand.has_noaddravail = true;
 863                 cand.preference -= 1000;
 864         }
 865
 866         if (pd_mode != IA_MODE_NONE) {
 867                 if (have_pd)
 868                         cand.preference += 2000 + (128 - have_pd);
 869                 else
 870                         cand.preference -= 2000;
 871         }
 872
 873         if (cand.duid_len > 0) {
 874                 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
 875                 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
 876                 dhcpv6_add_server_cand(&cand);
 877         }
 878
 879         return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
 880 }
 881
 882
 883 static int dhcpv6_commit_advert(void)
 884 {
 885         return dhcpv6_promote_server_cand();
 886 }
 887
 888
 889 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
 890                 const void *opt, const void *end, const struct sockaddr_in6 *from)
 891 {
 892         dhcpv6_handle_advert(orig, rc, opt, end, from);
 893         if (dhcpv6_commit_advert() < 0)
 894                 return -1;
 895
 896         return dhcpv6_handle_reply(orig, rc, opt, end, from);
 897 }
 898
 899
 900 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
 901                 const void *opt, const void *end, const struct sockaddr_in6 *from)
 902 {
 903         uint8_t *odata;
 904         uint16_t otype, olen;
 905         uint32_t refresh = 86400;
 906         int ret = 1;
 907         bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
 908
 909         odhcp6c_expire();
 910
 911         if (orig == DHCPV6_MSG_UNKNOWN) {
 912                 static time_t last_update = 0;
 913                 time_t now = odhcp6c_get_milli_time() / 1000;
 914
 915                 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 916                 last_update = now;
 917
 918                 if (t1 != UINT32_MAX)
 919                         t1 -= elapsed;
 920
 921                 if (t2 != UINT32_MAX)
 922                         t2 -= elapsed;
 923
 924                 if (t3 != UINT32_MAX)
 925                         t3 -= elapsed;
 926
 927                 if (t1 < 0)
 928                         t1 = 0;
 929
 930                 if (t2 < 0)
 931                         t2 = 0;
 932
 933                 if (t3 < 0)
 934                         t3 = 0;
 935         }
 936
 937         if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
 938                 // Delete NA and PD we have in the state from the Advert
 939                 odhcp6c_clear_state(STATE_IA_NA);
 940                 odhcp6c_clear_state(STATE_IA_PD);
 941         }
 942
 943         if (opt) {
 944                 odhcp6c_clear_state(STATE_DNS);
 945                 odhcp6c_clear_state(STATE_SEARCH);
 946                 odhcp6c_clear_state(STATE_SNTP_IP);
 947                 odhcp6c_clear_state(STATE_NTP_IP);
 948                 odhcp6c_clear_state(STATE_NTP_FQDN);
 949                 odhcp6c_clear_state(STATE_SIP_IP);
 950                 odhcp6c_clear_state(STATE_SIP_FQDN);
 951                 odhcp6c_clear_state(STATE_AFTR_NAME);
 952                 odhcp6c_clear_state(STATE_CER);
 953                 odhcp6c_clear_state(STATE_S46_MAPT);
 954                 odhcp6c_clear_state(STATE_S46_MAPE);
 955                 odhcp6c_clear_state(STATE_S46_LW);
 956                 odhcp6c_clear_state(STATE_PASSTHRU);
 957                 odhcp6c_clear_state(STATE_CUSTOM_OPTS);
 958
 959                 // Parse and find all matching IAs
 960                 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 961                         bool passthru = true;
 962
 963                         if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
 964                                         && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
 965                                 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 966
 967                                 if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) ||
 968                                         (pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD))
 969                                         continue;
 970
 971                                 // Test ID
 972                                 if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
 973                                         continue;
 974
 975                                 uint16_t code = DHCPV6_Success;
 976                                 uint16_t stype, slen;
 977                                 uint8_t *sdata;
 978                                 // Get and handle status code
 979                                 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
 980                                                 stype, slen, sdata) {
 981                                         if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
 982                                                 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
 983                                                 uint16_t mlen = (slen > 2) ? slen - 2 : 0;
 984
 985                                                 code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
 986
 987                                                 if (code == DHCPV6_Success)
 988                                                         continue;
 989
 990                                                 dhcpv6_handle_ia_status_code(orig, ia_hdr,
 991                                                         code, mdata, mlen, handled_status_codes, &ret);
 992
 993
 994                                                 if (ret > 0)
 995                                                         return ret;
 996                                                 break;
 997                                         }
 998                                 }
 999
1000                                 if (code != DHCPV6_Success)
1001                                         continue;
1002
1003                                 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
1004                                 passthru = false;
1005                         } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
1006                                 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
1007                                 uint16_t mlen = (olen > 2) ? olen - 2 : 0;
1008                                 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
1009
1010                                 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
1011                                 passthru = false;
1012                         }
1013                         else if (otype == DHCPV6_OPT_DNS_SERVERS) {
1014                                 if (olen % 16 == 0)
1015                                         odhcp6c_add_state(STATE_DNS, odata, olen);
1016                         } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
1017                                 odhcp6c_add_state(STATE_SEARCH, odata, olen);
1018                         } else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
1019                                 if (olen % 16 == 0)
1020                                         odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
1021                         } else if (otype == DHCPV6_OPT_NTP_SERVER) {
1022                                 uint16_t stype, slen;
1023                                 uint8_t *sdata;
1024                                 // Test status and bail if error
1025                                 dhcpv6_for_each_option(odata, odata + olen,
1026                                                 stype, slen, sdata) {
1027                                         if (slen == 16 && (stype == NTP_MC_ADDR ||
1028                                                         stype == NTP_SRV_ADDR))
1029                                                 odhcp6c_add_state(STATE_NTP_IP,
1030                                                                 sdata, slen);
1031                                         else if (slen > 0 && stype == NTP_SRV_FQDN)
1032                                                 odhcp6c_add_state(STATE_NTP_FQDN,
1033                                                                 sdata, slen);
1034                                 }
1035                         } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1036                                 if (olen == 16)
1037                                         odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1038                         } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
1039                                 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1040                         } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1041                                 refresh = ntohl_unaligned(odata);
1042                                 passthru = false;
1043                         } else if (otype == DHCPV6_OPT_AUTH) {
1044                                 if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1045                                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1046                                         if (r->protocol == 3 && r->algorithm == 1 &&
1047                                                         r->reconf_type == 1)
1048                                                 memcpy(reconf_key, r->key, sizeof(r->key));
1049                                 }
1050                                 passthru = false;
1051                         } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1052                                 size_t cur_len;
1053                                 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1054                                 if (cur_len == 0)
1055                                         odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1056                                 passthru = false;
1057                         } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1058                                 uint32_t sol_max_rt = ntohl_unaligned(odata);
1059                                 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1060                                                 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1061                                         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1062                                 passthru = false;
1063                         } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1064                                 uint32_t inf_max_rt = ntohl_unaligned(odata);
1065                                 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1066                                                 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1067                                         dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1068                                 passthru = false;
1069         #ifdef EXT_CER_ID
1070                         } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1071                                         sizeof(struct dhcpv6_cer_id)) {
1072                                 struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1073                                 struct in6_addr any = IN6ADDR_ANY_INIT;
1074                                 if (memcmp(&cer_id->addr, &any, sizeof(any)))
1075                                         odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1076                                 passthru = false;
1077         #endif
1078                         } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1079                                 odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1080                                 passthru = false;
1081                         } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1082                                 size_t mape_len;
1083                                 odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1084                                 if (mape_len == 0)
1085                                         odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1086                                 passthru = false;
1087                         } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1088                                 odhcp6c_add_state(STATE_S46_LW, odata, olen);
1089                                 passthru = false;
1090                         } else if (otype == DHCPV6_OPT_CLIENTID ||
1091                                         otype == DHCPV6_OPT_SERVERID ||
1092                                         otype == DHCPV6_OPT_IA_TA ||
1093                                         otype == DHCPV6_OPT_PREF ||
1094                                         otype == DHCPV6_OPT_UNICAST ||
1095                                         otype == DHCPV6_OPT_FQDN ||
1096                                         otype == DHCPV6_OPT_RECONF_ACCEPT) {
1097                                 passthru = false;
1098                         } else {
1099                                 odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1100                         }
1101
1102                         if (passthru)
1103                                 odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1104                 }
1105         }
1106
1107         if (orig != DHCPV6_MSG_INFO_REQ) {
1108                 // Update refresh timers if no fatal status code was received
1109                 if ((ret > 0) && dhcpv6_calc_refresh_timers()) {
1110                         switch (orig) {
1111                         case DHCPV6_MSG_RENEW:
1112                                 // Send further renews if T1 is not set
1113                                 if (!t1)
1114                                         ret = -1;
1115                                 break;
1116                         case DHCPV6_MSG_REBIND:
1117                                 // Send further rebinds if T1 and T2 is not set
1118                                 if (!t1 && !t2)
1119                                         ret = -1;
1120                                 break;
1121
1122                         case DHCPV6_MSG_REQUEST:
1123                                 // All server candidates can be cleared if not yet bound
1124                                 if (!odhcp6c_is_bound())
1125                                         dhcpv6_clear_all_server_cand();
1126
1127                         default :
1128                                 break;
1129                         }
1130
1131                         if (orig == DHCPV6_MSG_REBIND || orig == DHCPV6_MSG_REQUEST) {
1132                                 odhcp6c_clear_state(STATE_SERVER_ADDR);
1133                                 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1134                         }
1135                 }
1136         }
1137         else if (ret > 0) {
1138                 // All server candidates can be cleared if not yet bound
1139                 if (!odhcp6c_is_bound())
1140                         dhcpv6_clear_all_server_cand();
1141
1142                 t1 = refresh;
1143         }
1144
1145         return ret;
1146 }
1147
1148
1149 static int dhcpv6_parse_ia(void *opt, void *end)
1150 {
1151         struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1152         int parsed_ia = 0;
1153         uint32_t t1, t2;
1154         uint16_t otype, olen;
1155         uint8_t *odata;
1156
1157         t1 = ntohl(ia_hdr->t1);
1158         t2 = ntohl(ia_hdr->t2);
1159
1160         if (t1 > t2)
1161                 return 0;
1162
1163         // Update address IA
1164         dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1165                 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0, 0,
1166                                 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0};
1167
1168                 entry.iaid = ia_hdr->iaid;
1169
1170                 if (otype == DHCPV6_OPT_IA_PREFIX) {
1171                         struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1172                         if (olen + 4U < sizeof(*prefix))
1173                                 continue;
1174
1175                         entry.valid = ntohl(prefix->valid);
1176                         entry.preferred = ntohl(prefix->preferred);
1177
1178                         if (entry.preferred > entry.valid)
1179                                 continue;
1180
1181                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1182                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1183                         if (entry.t1 > entry.t2)
1184                                 entry.t1 = entry.t2;
1185
1186                         entry.length = prefix->prefix;
1187                         entry.target = prefix->addr;
1188                         uint16_t stype, slen;
1189                         uint8_t *sdata;
1190
1191                         // Parse PD-exclude
1192                         bool ok = true;
1193                         dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1194                                         odata + olen, stype, slen, sdata) {
1195                                 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1196                                         continue;
1197
1198                                 uint8_t elen = sdata[0];
1199                                 if (elen > 64)
1200                                         elen = 64;
1201
1202                                 if (entry.length < 32 || elen <= entry.length) {
1203                                         ok = false;
1204                                         continue;
1205                                 }
1206
1207
1208                                 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1209                                 if (slen <= bytes) {
1210                                         ok = false;
1211                                         continue;
1212                                 }
1213
1214                                 uint32_t exclude = 0;
1215                                 do {
1216                                         exclude = exclude << 8 | sdata[bytes];
1217                                 } while (--bytes);
1218
1219                                 exclude >>= 8 - ((elen - entry.length) % 8);
1220                                 exclude <<= 64 - elen;
1221
1222                                 // Abusing router & priority fields for exclusion
1223                                 entry.router = entry.target;
1224                                 entry.router.s6_addr32[1] |= htonl(exclude);
1225                                 entry.priority = elen;
1226                         }
1227
1228                         if (ok) {
1229                                 odhcp6c_update_entry(STATE_IA_PD, &entry, 0, false);
1230                                 parsed_ia++;
1231                         }
1232
1233                         entry.priority = 0;
1234                         memset(&entry.router, 0, sizeof(entry.router));
1235                 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1236                         struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1237                         if (olen + 4U < sizeof(*addr))
1238                                 continue;
1239
1240                         entry.preferred = ntohl(addr->preferred);
1241                         entry.valid = ntohl(addr->valid);
1242
1243                         if (entry.preferred > entry.valid)
1244                                 continue;
1245
1246                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1247                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1248                         if (entry.t1 > entry.t2)
1249                                 entry.t1 = entry.t2;
1250
1251                         entry.length = 128;
1252                         entry.target = addr->addr;
1253
1254                         odhcp6c_update_entry(STATE_IA_NA, &entry, 0, false);
1255                         parsed_ia++;
1256                 }
1257         }
1258         return parsed_ia;
1259 }
1260
1261
1262 static int dhcpv6_calc_refresh_timers(void)
1263 {
1264         struct odhcp6c_entry *e;
1265         size_t ia_na_entries, ia_pd_entries, i;
1266         int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1267
1268         e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1269         ia_na_entries /= sizeof(*e);
1270         for (i = 0; i < ia_na_entries; i++) {
1271                 if (e[i].t1 < l_t1)
1272                         l_t1 = e[i].t1;
1273
1274                 if (e[i].t2 < l_t2)
1275                         l_t2 = e[i].t2;
1276
1277                 if (e[i].valid > l_t3)
1278                         l_t3 = e[i].valid;
1279         }
1280
1281         e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1282         ia_pd_entries /= sizeof(*e);
1283         for (i = 0; i < ia_pd_entries; i++) {
1284                 if (e[i].t1 < l_t1)
1285                         l_t1 = e[i].t1;
1286
1287                 if (e[i].t2 < l_t2)
1288                         l_t2 = e[i].t2;
1289
1290                 if (e[i].valid > l_t3)
1291                         l_t3 = e[i].valid;
1292         }
1293
1294         if (ia_pd_entries || ia_na_entries) {
1295                 t1 = l_t1;
1296                 t2 = l_t2;
1297                 t3 = l_t3;
1298         } else {
1299                 t1 = 600;
1300         }
1301
1302         return (int)(ia_pd_entries + ia_na_entries);
1303 }
1304
1305
1306 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1307                 const void *status_msg, int len)
1308 {
1309         const char *src = status_msg;
1310         char buf[len + 3];
1311         char *dst = buf;
1312
1313         if (len) {
1314                 *dst++ = '(';
1315                 while (len--) {
1316                         *dst = isprint((unsigned char)*src) ? *src : '?';
1317                         src++;
1318                         dst++;
1319                 }
1320                 *dst++ = ')';
1321         }
1322         *dst = 0;
1323
1324         syslog(LOG_WARNING, "Server returned %s status %i %s",
1325                 scope, code, buf);
1326 }
1327
1328
1329 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1330                 const uint16_t code, const void *status_msg, const int len,
1331                 int *ret)
1332 {
1333         dhcpv6_log_status_code(code, "message", status_msg, len);
1334
1335         switch (code) {
1336         case DHCPV6_UnspecFail:
1337                 // Generic failure
1338                 *ret = 0;
1339                 break;
1340
1341         case DHCPV6_UseMulticast:
1342                 // TODO handle multicast status code
1343                 break;
1344
1345         case DHCPV6_NoAddrsAvail:
1346         case DHCPV6_NoPrefixAvail:
1347                 if (orig == DHCPV6_MSG_REQUEST)
1348                         *ret = 0; // Failure
1349                 break;
1350
1351         default:
1352                 break;
1353         }
1354 }
1355
1356
1357 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1358                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1359                 const void *status_msg, const int len,
1360                 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1361 {
1362         dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1363                 "IA_NA" : "IA_PD", status_msg, len);
1364
1365         switch (code) {
1366         case DHCPV6_NoBinding:
1367                 switch (orig) {
1368                 case DHCPV6_MSG_RENEW:
1369                 case DHCPV6_MSG_REBIND:
1370                         if ((*ret > 0) && !handled_status_codes[code])
1371                                 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1372                         break;
1373
1374                 default:
1375                         break;
1376                 }
1377                 break;
1378
1379         default:
1380                 *ret = 0;
1381                 break;
1382         }
1383 }
1384
1385 // Note this always takes ownership of cand->ia_na and cand->ia_pd
1386 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1387 {
1388         size_t cand_len, i;
1389         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1390
1391         // Remove identical duid server candidate
1392         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1393                 if (cand->duid_len == c[i].duid_len &&
1394                                 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1395                         free(c[i].ia_na);
1396                         free(c[i].ia_pd);
1397                         odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1398                         break;
1399                 }
1400         }
1401
1402         for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1403                 i < cand_len / sizeof(*c); ++i) {
1404                 if (c[i].preference < cand->preference)
1405                         break;
1406         }
1407
1408         if (odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand))) {
1409                 free(cand->ia_na);
1410                 free(cand->ia_pd);
1411         }
1412 }
1413
1414 static void dhcpv6_clear_all_server_cand(void)
1415 {
1416         size_t cand_len, i;
1417         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1418
1419         // Server candidates need deep delete for IA_NA/IA_PD
1420         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1421                 free(c[i].ia_na);
1422                 free(c[i].ia_pd);
1423         }
1424         odhcp6c_clear_state(STATE_SERVER_CAND);
1425 }
1426
1427 int dhcpv6_promote_server_cand(void)
1428 {
1429         size_t cand_len;
1430         struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1431         uint16_t hdr[2];
1432         int ret = DHCPV6_STATELESS;
1433
1434         // Clear lingering candidate state info
1435         odhcp6c_clear_state(STATE_SERVER_ID);
1436         odhcp6c_clear_state(STATE_IA_NA);
1437         odhcp6c_clear_state(STATE_IA_PD);
1438
1439         if (!cand_len)
1440                 return -1;
1441
1442         if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1443                 na_mode = IA_MODE_NONE;
1444
1445                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1446                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1447
1448                 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1449         }
1450
1451         hdr[0] = htons(DHCPV6_OPT_SERVERID);
1452         hdr[1] = htons(cand->duid_len);
1453         odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1454         odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1455         accept_reconfig = cand->wants_reconfigure;
1456         if (cand->ia_na_len) {
1457                 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1458                 free(cand->ia_na);
1459                 if (na_mode != IA_MODE_NONE)
1460                         ret = DHCPV6_STATEFUL;
1461         }
1462         if (cand->ia_pd_len) {
1463                 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1464                 free(cand->ia_pd);
1465                 if (request_prefix)
1466                         ret = DHCPV6_STATEFUL;
1467         }
1468
1469         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1470         dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1471
1472         odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1473
1474         return ret;
1475 }