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