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