src/odhcp6c.c

   1 /**
   2  * Copyright (C) 2012-2013 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 <errno.h>
  17 #include <fcntl.h>
  18 #include <stdio.h>
  19 #include <stdlib.h>
  20 #include <stddef.h>
  21 #include <unistd.h>
  22 #include <syslog.h>
  23 #include <signal.h>
  24 #include <string.h>
  25 #include <stdbool.h>
  26
  27 #include <net/if.h>
  28 #include <sys/wait.h>
  29 #include <sys/syscall.h>
  30 #include <arpa/inet.h>
  31
  32 #include "odhcp6c.h"
  33 #include "ra.h"
  34
  35 #ifdef EXT_BFD_PING
  36 #include "bfd.h"
  37 #endif
  38
  39
  40 static void sighandler(int signal);
  41 static int usage(void);
  42
  43 static uint8_t *state_data[_STATE_MAX] = {NULL};
  44 static size_t state_len[_STATE_MAX] = {0};
  45
  46 static volatile bool signal_io = false;
  47 static volatile bool signal_usr1 = false;
  48 static volatile bool signal_usr2 = false;
  49 static volatile bool signal_term = false;
  50
  51 static int urandom_fd = -1, allow_slaac_only = 0;
  52 static bool bound = false, release = true;
  53 static time_t last_update = 0;
  54
  55 int main(_unused int argc, char* const argv[])
  56 {
  57         // Allocate ressources
  58         const char *pidfile = NULL;
  59         const char *script = "/usr/sbin/odhcp6c-update";
  60         ssize_t l;
  61         uint8_t buf[134];
  62         char *optpos;
  63         uint16_t opttype;
  64         enum odhcp6c_ia_mode ia_na_mode = IA_MODE_TRY;
  65         enum odhcp6c_ia_mode ia_pd_mode = IA_MODE_TRY;
  66         int ia_pd_iaid_index = 0;
  67         static struct in6_addr ifid = IN6ADDR_ANY_INIT;
  68         int sol_timeout = DHCPV6_SOL_MAX_RT;
  69
  70 #ifdef EXT_BFD_PING
  71         int bfd_interval = 0, bfd_loss = 3;
  72 #endif
  73
  74         bool help = false, daemonize = false;
  75         int logopt = LOG_PID;
  76         int c;
  77         unsigned int client_options = DHCPV6_CLIENT_FQDN | DHCPV6_ACCEPT_RECONFIGURE;
  78
  79         while ((c = getopt(argc, argv, "S::N:P:FB:c:i:r:Rs:kt:hedp:fa")) != -1) {
  80                 switch (c) {
  81                 case 'S':
  82                         allow_slaac_only = (optarg) ? atoi(optarg) : -1;
  83                         break;
  84
  85                 case 'N':
  86                         if (!strcmp(optarg, "force")) {
  87                                 ia_na_mode = IA_MODE_FORCE;
  88                                 allow_slaac_only = -1;
  89                         } else if (!strcmp(optarg, "none")) {
  90                                 ia_na_mode = IA_MODE_NONE;
  91                         } else if (!strcmp(optarg, "try")) {
  92                                 ia_na_mode = IA_MODE_TRY;
  93                         } else{
  94                                 help = true;
  95                         }
  96                         break;
  97
  98                 case 'P':
  99                         if (allow_slaac_only >= 0 && allow_slaac_only < 10)
 100                                 allow_slaac_only = 10;
 101
 102                         char *iaid_begin;
 103                         int iaid_len = 0;
 104
 105                         int prefix_length = strtoul(optarg, &iaid_begin, 10);
 106
 107                         if (*iaid_begin != '\0' && *iaid_begin != ',') {
 108                                 syslog(LOG_ERR, "invalid argument: '%s'", optarg);
 109                                 return 1;
 110                         }
 111
 112                         struct odhcp6c_request_prefix prefix = { 0, prefix_length };
 113
 114                         if (*iaid_begin == ',' && (iaid_len = strlen(iaid_begin)) > 1)
 115                                 memcpy(&prefix.iaid, iaid_begin + 1, iaid_len > 4 ? 4 : iaid_len);
 116                         else
 117                                 prefix.iaid = ++ia_pd_iaid_index;
 118
 119                         odhcp6c_add_state(STATE_IA_PD_INIT, &prefix, sizeof(prefix));
 120
 121                         break;
 122
 123                 case 'F':
 124                         allow_slaac_only = -1;
 125                         ia_pd_mode = IA_MODE_FORCE;
 126                         break;
 127
 128 #ifdef EXT_BFD_PING
 129                 case 'B':
 130                         bfd_interval = atoi(optarg);
 131                         break;
 132 #endif
 133
 134                 case 'c':
 135                         l = script_unhexlify(&buf[4], sizeof(buf) - 4, optarg);
 136                         if (l > 0) {
 137                                 buf[0] = 0;
 138                                 buf[1] = DHCPV6_OPT_CLIENTID;
 139                                 buf[2] = 0;
 140                                 buf[3] = l;
 141                                 odhcp6c_add_state(STATE_CLIENT_ID, buf, l + 4);
 142                         } else {
 143                                 help = true;
 144                         }
 145                         break;
 146
 147                 case 'i':
 148                         if (inet_pton(AF_INET6, optarg, &ifid) != 1)
 149                                 help = true;
 150                         break;
 151
 152                 case 'r':
 153                         optpos = optarg;
 154                         while (optpos[0]) {
 155                                 opttype = htons(strtoul(optarg, &optpos, 10));
 156                                 if (optpos == optarg)
 157                                         break;
 158                                 else if (optpos[0])
 159                                         optarg = &optpos[1];
 160                                 odhcp6c_add_state(STATE_ORO, &opttype, 2);
 161                         }
 162                         break;
 163
 164                 case 'R':
 165                         client_options |= DHCPV6_STRICT_OPTIONS;
 166                         break;
 167
 168                 case 's':
 169                         script = optarg;
 170                         break;
 171
 172                 case 'k':
 173                         release = false;
 174                         break;
 175
 176                 case 't':
 177                         sol_timeout = atoi(optarg);
 178                         break;
 179
 180                 case 'e':
 181                         logopt |= LOG_PERROR;
 182                         break;
 183
 184                 case 'd':
 185                         daemonize = true;
 186                         break;
 187
 188                 case 'p':
 189                         pidfile = optarg;
 190                         break;
 191
 192                 case 'f':
 193                         client_options &= ~DHCPV6_CLIENT_FQDN;
 194                         break;
 195
 196                 case 'a':
 197                         client_options &= ~DHCPV6_ACCEPT_RECONFIGURE;
 198                         break;
 199
 200                 default:
 201                         help = true;
 202                         break;
 203                 }
 204         }
 205
 206         openlog("odhcp6c", logopt, LOG_DAEMON);
 207         const char *ifname = argv[optind];
 208
 209         if (help || !ifname)
 210                 return usage();
 211
 212         signal(SIGIO, sighandler);
 213         signal(SIGHUP, sighandler);
 214         signal(SIGINT, sighandler);
 215         signal(SIGCHLD, sighandler);
 216         signal(SIGTERM, sighandler);
 217         signal(SIGUSR1, sighandler);
 218         signal(SIGUSR2, sighandler);
 219
 220         if ((urandom_fd = open("/dev/urandom", O_CLOEXEC | O_RDONLY)) < 0 ||
 221                         init_dhcpv6(ifname, client_options, sol_timeout) ||
 222                         ra_init(ifname, &ifid) || script_init(script, ifname)) {
 223                 syslog(LOG_ERR, "failed to initialize: %s", strerror(errno));
 224                 return 3;
 225         }
 226
 227         if (daemonize) {
 228                 openlog("odhcp6c", LOG_PID, LOG_DAEMON); // Disable LOG_PERROR
 229                 if (daemon(0, 0)) {
 230                         syslog(LOG_ERR, "Failed to daemonize: %s",
 231                                         strerror(errno));
 232                         return 4;
 233                 }
 234
 235                 char pidbuf[128];
 236                 if (!pidfile) {
 237                         snprintf(pidbuf, sizeof(pidbuf),
 238                                         "/var/run/odhcp6c.%s.pid", ifname);
 239                         pidfile = pidbuf;
 240                 }
 241
 242                 int fd = open(pidfile, O_WRONLY | O_CREAT);
 243                 if (fd >= 0) {
 244                         char buf[8];
 245                         int len = snprintf(buf, sizeof(buf), "%i\n", getpid());
 246                         write(fd, buf, len);
 247                         close(fd);
 248                 }
 249         }
 250
 251         script_call("started");
 252
 253         while (!signal_term) { // Main logic
 254                 odhcp6c_clear_state(STATE_SERVER_ID);
 255                 odhcp6c_clear_state(STATE_IA_NA);
 256                 odhcp6c_clear_state(STATE_IA_PD);
 257                 odhcp6c_clear_state(STATE_SNTP_IP);
 258                 odhcp6c_clear_state(STATE_NTP_IP);
 259                 odhcp6c_clear_state(STATE_NTP_FQDN);
 260                 odhcp6c_clear_state(STATE_SIP_IP);
 261                 odhcp6c_clear_state(STATE_SIP_FQDN);
 262                 dhcpv6_set_ia_mode(ia_na_mode, ia_pd_mode);
 263                 bound = false;
 264
 265                 syslog(LOG_NOTICE, "(re)starting transaction on %s", ifname);
 266
 267                 signal_usr1 = signal_usr2 = false;
 268                 int mode = dhcpv6_request(DHCPV6_MSG_SOLICIT);
 269                 odhcp6c_signal_process();
 270
 271                 if (mode < 0)
 272                         continue;
 273
 274                 do {
 275                         int res = dhcpv6_request(mode == DHCPV6_STATELESS ?
 276                                         DHCPV6_MSG_INFO_REQ : DHCPV6_MSG_REQUEST);
 277                         bool signalled = odhcp6c_signal_process();
 278
 279                         if (res > 0)
 280                                 break;
 281                         else if (signalled) {
 282                                 mode = -1;
 283                                 break;
 284                         }
 285
 286                         mode = dhcpv6_promote_server_cand();
 287                 } while (mode > DHCPV6_UNKNOWN);
 288
 289                 if (mode < 0)
 290                         continue;
 291
 292                 switch (mode) {
 293                 case DHCPV6_STATELESS:
 294                         bound = true;
 295                         syslog(LOG_NOTICE, "entering stateless-mode on %s", ifname);
 296
 297                         while (!signal_usr2 && !signal_term) {
 298                                 signal_usr1 = false;
 299                                 script_call("informed");
 300
 301                                 int res = dhcpv6_poll_reconfigure();
 302                                 odhcp6c_signal_process();
 303
 304                                 if (res > 0)
 305                                         continue;
 306
 307                                 if (signal_usr1) {
 308                                         signal_usr1 = false; // Acknowledged
 309                                         continue;
 310                                 }
 311                                 if (signal_usr2 || signal_term)
 312                                         break;
 313
 314                                 res = dhcpv6_request(DHCPV6_MSG_INFO_REQ);
 315                                 odhcp6c_signal_process();
 316                                 if (signal_usr1)
 317                                         continue;
 318                                 else if (res < 0)
 319                                         break;
 320                         }
 321                         break;
 322
 323                 case DHCPV6_STATEFUL:
 324                         script_call("bound");
 325                         bound = true;
 326                         syslog(LOG_NOTICE, "entering stateful-mode on %s", ifname);
 327 #ifdef EXT_BFD_PING
 328                         if (bfd_interval > 0)
 329                                 bfd_start(ifname, bfd_loss, bfd_interval);
 330 #endif
 331
 332                         while (!signal_usr2 && !signal_term) {
 333                                 // Renew Cycle
 334                                 // Wait for T1 to expire or until we get a reconfigure
 335                                 int res = dhcpv6_poll_reconfigure();
 336                                 odhcp6c_signal_process();
 337                                 if (res > 0) {
 338                                         script_call("updated");
 339                                         continue;
 340                                 }
 341
 342                                 // Handle signal, if necessary
 343                                 if (signal_usr1)
 344                                         signal_usr1 = false; // Acknowledged
 345                                 if (signal_usr2 || signal_term)
 346                                         break; // Other signal type
 347
 348                                 // Send renew as T1 expired
 349                                 size_t ia_pd_len, ia_na_len;
 350                                 odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 351                                 odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 352
 353                                 // If we have any IAs, send renew, otherwise request
 354                                 if (ia_pd_len == 0 && ia_na_len == 0)
 355                                         res = dhcpv6_request(DHCPV6_MSG_REQUEST);
 356                                 else
 357                                         res = dhcpv6_request(DHCPV6_MSG_RENEW);
 358
 359                                 odhcp6c_signal_process();
 360                                 if (res > 0) { // Renew was succesfull
 361                                         // Publish updates
 362                                         script_call("updated");
 363                                         continue; // Renew was successful
 364                                 }
 365
 366                                 odhcp6c_clear_state(STATE_SERVER_ID); // Remove binding
 367
 368                                 // If we have IAs, try rebind otherwise restart
 369                                 res = dhcpv6_request(DHCPV6_MSG_REBIND);
 370                                 odhcp6c_signal_process();
 371
 372                                 if (res > 0)
 373                                         script_call("rebound");
 374                                 else {
 375 #ifdef EXT_BFD_PING
 376                                         bfd_stop();
 377 #endif
 378                                         break;
 379                                 }
 380                         }
 381                         break;
 382
 383                 default:
 384                         break;
 385                 }
 386
 387                 size_t ia_pd_len, ia_na_len, server_id_len;
 388                 odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 389                 odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 390                 odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 391
 392                 // Add all prefixes to lost prefixes
 393                 bound = false;
 394                 script_call("unbound");
 395
 396                 if (server_id_len > 0 && (ia_pd_len > 0 || ia_na_len > 0) && release)
 397                         dhcpv6_request(DHCPV6_MSG_RELEASE);
 398
 399                 odhcp6c_clear_state(STATE_IA_NA);
 400                 odhcp6c_clear_state(STATE_IA_PD);
 401         }
 402
 403         script_call("stopped");
 404         return 0;
 405 }
 406
 407
 408 static int usage(void)
 409 {
 410         const char buf[] =
 411         "Usage: odhcp6c [options] <interface>\n"
 412         "\nFeature options:\n"
 413         "       -S <time>       Wait at least <time> sec for a DHCP-server (0)\n"
 414         "       -N <mode>       Mode for requesting addresses [try|force|none]\n"
 415         "       -P <length>     Request IPv6-Prefix (0 = auto)\n"
 416         "       -F              Force IPv6-Prefix\n"
 417 #ifdef EXT_BFD_PING
 418         "       -B <interval>   Enable BFD ping check\n"
 419 #endif
 420         "       -c <clientid>   Override client-ID (base-16 encoded)\n"
 421         "       -i <iface-id>   Use a custom interface identifier for RA handling\n"
 422         "       -r <options>    Options to be requested (comma-separated)\n"
 423         "       -R              Do not request any options except those specified with -r\n"
 424         "       -s <script>     Status update script (/usr/sbin/odhcp6c-update)\n"
 425         "       -a              Don't send Accept Reconfigure option\n"
 426         "       -f              Don't send Client FQDN option\n"
 427         "       -k              Don't send a RELEASE when stopping\n"
 428         "       -t <seconds>    Maximum timeout for DHCPv6-SOLICIT (120)\n"
 429         "\nInvocation options:\n"
 430         "       -p <pidfile>    Set pidfile (/var/run/6relayd.pid)\n"
 431         "       -d              Daemonize\n"
 432         "       -e              Write logmessages to stderr\n"
 433         //"     -v              Increase logging verbosity\n"
 434         "       -h              Show this help\n\n";
 435         write(STDERR_FILENO, buf, sizeof(buf));
 436         return 1;
 437 }
 438
 439
 440 // Don't want to pull-in librt and libpthread just for a monotonic clock...
 441 uint64_t odhcp6c_get_milli_time(void)
 442 {
 443         struct timespec t = {0, 0};
 444         syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &t);
 445         return t.tv_sec * 1000 + t.tv_nsec / 1000000;
 446 }
 447
 448
 449 static uint8_t* odhcp6c_resize_state(enum odhcp6c_state state, ssize_t len)
 450 {
 451         if (len == 0)
 452                 return state_data[state] + state_len[state];
 453         else if (state_len[state] + len > 1024)
 454                 return NULL;
 455
 456         uint8_t *n = realloc(state_data[state], state_len[state] + len);
 457         if (n || state_len[state] + len == 0) {
 458                 state_data[state] = n;
 459                 n += state_len[state];
 460                 state_len[state] += len;
 461         }
 462         return n;
 463 }
 464
 465
 466 bool odhcp6c_signal_process(void)
 467 {
 468         while (signal_io) {
 469                 signal_io = false;
 470
 471                 bool ra_updated = ra_process();
 472
 473                 if (ra_link_up())
 474                         signal_usr2 = true;
 475
 476                 if (ra_updated && (bound || allow_slaac_only == 0))
 477                         script_call("ra-updated"); // Immediate process urgent events
 478                 else if (ra_updated && !bound && allow_slaac_only > 0)
 479                         script_delay_call("ra-updated", allow_slaac_only);
 480
 481 #ifdef EXT_BFD_PING
 482                 bfd_receive();
 483 #endif
 484         }
 485
 486         return signal_usr1 || signal_usr2 || signal_term;
 487 }
 488
 489
 490 void odhcp6c_clear_state(enum odhcp6c_state state)
 491 {
 492         state_len[state] = 0;
 493 }
 494
 495
 496 void odhcp6c_add_state(enum odhcp6c_state state, const void *data, size_t len)
 497 {
 498         uint8_t *n = odhcp6c_resize_state(state, len);
 499         if (n)
 500                 memcpy(n, data, len);
 501 }
 502
 503 void odhcp6c_insert_state(enum odhcp6c_state state, size_t offset, const void *data, size_t len)
 504 {
 505         ssize_t len_after = state_len[state] - offset;
 506         if (len_after < 0)
 507                 return;
 508
 509         uint8_t *n = odhcp6c_resize_state(state, len);
 510         if (n) {
 511                 uint8_t *sdata = state_data[state];
 512
 513                 memmove(sdata + offset + len, sdata + offset, len_after);
 514                 memcpy(sdata + offset, data, len);
 515         }
 516 }
 517
 518 size_t odhcp6c_remove_state(enum odhcp6c_state state, size_t offset, size_t len)
 519 {
 520         uint8_t *data = state_data[state];
 521         ssize_t len_after = state_len[state] - (offset + len);
 522         if (len_after < 0)
 523                 return state_len[state];
 524
 525         memmove(data + offset, data + offset + len, len_after);
 526         return state_len[state] -= len;
 527 }
 528
 529
 530 void* odhcp6c_move_state(enum odhcp6c_state state, size_t *len)
 531 {
 532         *len = state_len[state];
 533         void *data = state_data[state];
 534
 535         state_len[state] = 0;
 536         state_data[state] = NULL;
 537
 538         return data;
 539 }
 540
 541
 542 void* odhcp6c_get_state(enum odhcp6c_state state, size_t *len)
 543 {
 544         *len = state_len[state];
 545         return state_data[state];
 546 }
 547
 548
 549 struct odhcp6c_entry* odhcp6c_find_entry(enum odhcp6c_state state, const struct odhcp6c_entry *new)
 550 {
 551         size_t len, cmplen = offsetof(struct odhcp6c_entry, target) + new->length / 8;
 552         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 553         struct odhcp6c_entry *x = NULL;
 554
 555         for (struct odhcp6c_entry *c = start; !x && c < &start[len/sizeof(*c)]; ++c)
 556                 if (!memcmp(c, new, cmplen))
 557                         return c;
 558
 559         return NULL;
 560 }
 561
 562
 563 bool odhcp6c_update_entry_safe(enum odhcp6c_state state, struct odhcp6c_entry *new, uint32_t safe)
 564 {
 565         size_t len;
 566         struct odhcp6c_entry *x = odhcp6c_find_entry(state, new);
 567         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 568
 569         if (x && x->valid > new->valid && new->valid < safe)
 570                 new->valid = safe;
 571
 572         if (new->valid > 0) {
 573                 if (x) {
 574                         if (new->valid >= x->valid && new->valid - x->valid < 60 &&
 575                                         new->preferred >= x->preferred &&
 576                                         new->preferred - x->preferred < 60 &&
 577                                         x->class == new->class)
 578                                 return false;
 579                         x->valid = new->valid;
 580                         x->preferred = new->preferred;
 581                         x->t1 = new->t1;
 582                         x->t2 = new->t2;
 583                         x->class = new->class;
 584                         x->iaid = new->iaid;
 585                 } else {
 586                         odhcp6c_add_state(state, new, sizeof(*new));
 587                 }
 588         } else if (x) {
 589                 odhcp6c_remove_state(state, (x - start) * sizeof(*x), sizeof(*x));
 590         }
 591         return true;
 592 }
 593
 594
 595 bool odhcp6c_update_entry(enum odhcp6c_state state, struct odhcp6c_entry *new)
 596 {
 597         return odhcp6c_update_entry_safe(state, new, 0);
 598 }
 599
 600
 601 static void odhcp6c_expire_list(enum odhcp6c_state state, uint32_t elapsed)
 602 {
 603         size_t len;
 604         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 605         for (struct odhcp6c_entry *c = start; c < &start[len / sizeof(*c)]; ++c) {
 606                 if (c->t1 < elapsed)
 607                         c->t1 = 0;
 608                 else if (c->t1 != UINT32_MAX)
 609                         c->t1 -= elapsed;
 610
 611                 if (c->t2 < elapsed)
 612                         c->t2 = 0;
 613                 else if (c->t2 != UINT32_MAX)
 614                         c->t2 -= elapsed;
 615
 616                 if (c->preferred < elapsed)
 617                         c->preferred = 0;
 618                 else if (c->preferred != UINT32_MAX)
 619                         c->preferred -= elapsed;
 620
 621                 if (c->valid < elapsed)
 622                         c->valid = 0;
 623                 else if (c->valid != UINT32_MAX)
 624                         c->valid -= elapsed;
 625
 626                 if (!c->valid)
 627                         odhcp6c_remove_state(state, (c - start) * sizeof(*c), sizeof(*c));
 628         }
 629 }
 630
 631
 632 void odhcp6c_expire(void)
 633 {
 634         time_t now = odhcp6c_get_milli_time() / 1000;
 635         uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 636         last_update = now;
 637
 638         odhcp6c_expire_list(STATE_RA_PREFIX, elapsed);
 639         odhcp6c_expire_list(STATE_RA_ROUTE, elapsed);
 640         odhcp6c_expire_list(STATE_RA_DNS, elapsed);
 641         odhcp6c_expire_list(STATE_IA_NA, elapsed);
 642         odhcp6c_expire_list(STATE_IA_PD, elapsed);
 643 }
 644
 645
 646 uint32_t odhcp6c_elapsed(void)
 647 {
 648         return odhcp6c_get_milli_time() / 1000 - last_update;
 649 }
 650
 651
 652 void odhcp6c_random(void *buf, size_t len)
 653 {
 654         read(urandom_fd, buf, len);
 655 }
 656
 657 bool odhcp6c_is_bound(void)
 658 {
 659         return bound;
 660 }
 661
 662 static void sighandler(int signal)
 663 {
 664         if (signal == SIGCHLD)
 665                 while (waitpid(-1, NULL, WNOHANG) > 0);
 666         else if (signal == SIGUSR1)
 667                 signal_usr1 = true;
 668         else if (signal == SIGUSR2)
 669                 signal_usr2 = true;
 670         else if (signal == SIGIO)
 671                 signal_io = true;
 672         else
 673                 signal_term = true;
 674 }