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