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