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                                 size_t ia_pd_len, ia_na_len;
 315                                 odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 316                                 odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 317
 318                                 // If we have any IAs, send renew, otherwise request
 319                                 if (ia_pd_len == 0 && ia_na_len == 0)
 320                                         res = dhcpv6_request(DHCPV6_MSG_REQUEST);
 321                                 else
 322                                         res = dhcpv6_request(DHCPV6_MSG_RENEW);
 323
 324                                 odhcp6c_signal_process();
 325                                 if (res > 0) { // Renew was succesfull
 326                                         // Publish updates
 327                                         script_call("updated");
 328                                         continue; // Renew was successful
 329                                 }
 330
 331                                 odhcp6c_clear_state(STATE_SERVER_ID); // Remove binding
 332
 333                                 // If we have IAs, try rebind otherwise restart
 334                                 res = dhcpv6_request(DHCPV6_MSG_REBIND);
 335                                 odhcp6c_signal_process();
 336
 337                                 if (res > 0)
 338                                         script_call("rebound");
 339                                 else {
 340 #ifdef EXT_BFD_PING
 341                                         bfd_stop();
 342 #endif
 343                                         break;
 344                                 }
 345                         }
 346                         break;
 347
 348                 default:
 349                         break;
 350                 }
 351
 352                 size_t ia_pd_len, ia_na_len, server_id_len;
 353                 odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 354                 odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 355                 odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 356
 357                 // Add all prefixes to lost prefixes
 358                 bound = false;
 359                 script_call("unbound");
 360
 361                 if (server_id_len > 0 && (ia_pd_len > 0 || ia_na_len > 0) && release)
 362                         dhcpv6_request(DHCPV6_MSG_RELEASE);
 363
 364                 odhcp6c_clear_state(STATE_IA_NA);
 365                 odhcp6c_clear_state(STATE_IA_PD);
 366         }
 367
 368         script_call("stopped");
 369         return 0;
 370 }
 371
 372
 373 static int usage(void)
 374 {
 375         const char buf[] =
 376         "Usage: odhcp6c [options] <interface>\n"
 377         "\nFeature options:\n"
 378         "       -S <time>       Wait at least <time> sec for a DHCP-server (0)\n"
 379         "       -N <mode>       Mode for requesting addresses [try|force|none]\n"
 380         "       -P <length>     Request IPv6-Prefix (0 = auto)\n"
 381         "       -F              Force IPv6-Prefix\n"
 382 #ifdef EXT_BFD_PING
 383         "       -B <interval>   Enable BFD ping check\n"
 384 #endif
 385         "       -c <clientid>   Override client-ID (base-16 encoded)\n"
 386         "       -i <iface-id>   Use a custom interface identifier for RA handling\n"
 387         "       -r <options>    Options to be requested (comma-separated)\n"
 388         "       -s <script>     Status update script (/usr/sbin/odhcp6c-update)\n"
 389         "       -k              Don't send a RELEASE when stopping\n"
 390         "       -t <seconds>    Maximum timeout for DHCPv6-SOLICIT (120)\n"
 391         "\nInvocation options:\n"
 392         "       -p <pidfile>    Set pidfile (/var/run/6relayd.pid)\n"
 393         "       -d              Daemonize\n"
 394         "       -e              Write logmessages to stderr\n"
 395         //"     -v              Increase logging verbosity\n"
 396         "       -h              Show this help\n\n";
 397         write(STDERR_FILENO, buf, sizeof(buf));
 398         return 1;
 399 }
 400
 401
 402 // Don't want to pull-in librt and libpthread just for a monotonic clock...
 403 uint64_t odhcp6c_get_milli_time(void)
 404 {
 405         struct timespec t = {0, 0};
 406         syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &t);
 407         return t.tv_sec * 1000 + t.tv_nsec / 1000000;
 408 }
 409
 410
 411 static uint8_t* odhcp6c_resize_state(enum odhcp6c_state state, ssize_t len)
 412 {
 413         if (len == 0)
 414                 return state_data[state] + state_len[state];
 415         else if (state_len[state] + len > 1024)
 416                 return NULL;
 417
 418         uint8_t *n = realloc(state_data[state], state_len[state] + len);
 419         if (n || state_len[state] + len == 0) {
 420                 state_data[state] = n;
 421                 n += state_len[state];
 422                 state_len[state] += len;
 423         }
 424         return n;
 425 }
 426
 427
 428 bool odhcp6c_signal_process(void)
 429 {
 430         if (do_signal == SIGIO) {
 431                 do_signal = 0;
 432                 bool ra_updated = ra_process();
 433
 434                 if (ra_link_up())
 435                         do_signal = SIGUSR2;
 436
 437                 if (ra_updated && (bound || allow_slaac_only == 0))
 438                         script_call("ra-updated"); // Immediate process urgent events
 439                 else if (ra_updated && !bound && allow_slaac_only > 0)
 440                         script_delay_call("ra-updated", allow_slaac_only);
 441
 442 #ifdef EXT_BFD_PING
 443                 bfd_receive();
 444 #endif
 445         }
 446
 447         return do_signal != 0;
 448 }
 449
 450
 451 void odhcp6c_clear_state(enum odhcp6c_state state)
 452 {
 453         state_len[state] = 0;
 454 }
 455
 456
 457 void odhcp6c_add_state(enum odhcp6c_state state, const void *data, size_t len)
 458 {
 459         uint8_t *n = odhcp6c_resize_state(state, len);
 460         if (n)
 461                 memcpy(n, data, len);
 462 }
 463
 464 void odhcp6c_insert_state(enum odhcp6c_state state, size_t offset, const void *data, size_t len)
 465 {
 466         ssize_t len_after = state_len[state] - offset;
 467         if (len_after < 0)
 468                 return;
 469
 470         uint8_t *n = odhcp6c_resize_state(state, len);
 471         if (n) {
 472                 uint8_t *sdata = state_data[state];
 473
 474                 memmove(sdata + offset + len, sdata + offset, len_after);
 475                 memcpy(sdata + offset, data, len);
 476         }
 477 }
 478
 479 size_t odhcp6c_remove_state(enum odhcp6c_state state, size_t offset, size_t len)
 480 {
 481         uint8_t *data = state_data[state];
 482         ssize_t len_after = state_len[state] - (offset + len);
 483         if (len_after < 0)
 484                 return state_len[state];
 485
 486         memmove(data + offset, data + offset + len, len_after);
 487         return state_len[state] -= len;
 488 }
 489
 490
 491 void* odhcp6c_move_state(enum odhcp6c_state state, size_t *len)
 492 {
 493         *len = state_len[state];
 494         void *data = state_data[state];
 495
 496         state_len[state] = 0;
 497         state_data[state] = NULL;
 498
 499         return data;
 500 }
 501
 502
 503 void* odhcp6c_get_state(enum odhcp6c_state state, size_t *len)
 504 {
 505         *len = state_len[state];
 506         return state_data[state];
 507 }
 508
 509
 510 struct odhcp6c_entry* odhcp6c_find_entry(enum odhcp6c_state state, const struct odhcp6c_entry *new)
 511 {
 512         size_t len, cmplen = offsetof(struct odhcp6c_entry, target) + new->length / 8;
 513         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 514         struct odhcp6c_entry *x = NULL;
 515
 516         for (struct odhcp6c_entry *c = start; !x && c < &start[len/sizeof(*c)]; ++c)
 517                 if (!memcmp(c, new, cmplen))
 518                         return c;
 519
 520         return NULL;
 521 }
 522
 523
 524 bool odhcp6c_update_entry_safe(enum odhcp6c_state state, struct odhcp6c_entry *new, uint32_t safe)
 525 {
 526         size_t len;
 527         struct odhcp6c_entry *x = odhcp6c_find_entry(state, new);
 528         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 529
 530         if (x && x->valid > new->valid && new->valid < safe)
 531                 new->valid = safe;
 532
 533         if (new->valid > 0) {
 534                 if (x) {
 535                         if (new->valid >= x->valid && new->valid - x->valid < 60 &&
 536                                         new->preferred >= x->preferred &&
 537                                         new->preferred - x->preferred < 60 &&
 538                                         x->class == new->class)
 539                                 return false;
 540                         x->valid = new->valid;
 541                         x->preferred = new->preferred;
 542                         x->t1 = new->t1;
 543                         x->t2 = new->t2;
 544                         x->class = new->class;
 545                 } else {
 546                         odhcp6c_add_state(state, new, sizeof(*new));
 547                 }
 548         } else if (x) {
 549                 odhcp6c_remove_state(state, (x - start) * sizeof(*x), sizeof(*x));
 550         }
 551         return true;
 552 }
 553
 554
 555 bool odhcp6c_update_entry(enum odhcp6c_state state, struct odhcp6c_entry *new)
 556 {
 557         return odhcp6c_update_entry_safe(state, new, 0);
 558 }
 559
 560
 561 static void odhcp6c_expire_list(enum odhcp6c_state state, uint32_t elapsed)
 562 {
 563         size_t len;
 564         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 565         for (struct odhcp6c_entry *c = start; c < &start[len / sizeof(*c)]; ++c) {
 566                 if (c->t1 < elapsed)
 567                         c->t1 = 0;
 568                 else if (c->t1 != UINT32_MAX)
 569                         c->t1 -= elapsed;
 570
 571                 if (c->t2 < elapsed)
 572                         c->t2 = 0;
 573                 else if (c->t2 != UINT32_MAX)
 574                         c->t2 -= elapsed;
 575
 576                 if (c->preferred < elapsed)
 577                         c->preferred = 0;
 578                 else if (c->preferred != UINT32_MAX)
 579                         c->preferred -= elapsed;
 580
 581                 if (c->valid < elapsed)
 582                         c->valid = 0;
 583                 else if (c->valid != UINT32_MAX)
 584                         c->valid -= elapsed;
 585
 586                 if (!c->valid)
 587                         odhcp6c_remove_state(state, (c - start) * sizeof(*c), sizeof(*c));
 588         }
 589 }
 590
 591
 592 void odhcp6c_expire(void)
 593 {
 594         time_t now = odhcp6c_get_milli_time() / 1000;
 595         uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 596         last_update = now;
 597
 598         odhcp6c_expire_list(STATE_RA_PREFIX, elapsed);
 599         odhcp6c_expire_list(STATE_RA_ROUTE, elapsed);
 600         odhcp6c_expire_list(STATE_RA_DNS, elapsed);
 601         odhcp6c_expire_list(STATE_IA_NA, elapsed);
 602         odhcp6c_expire_list(STATE_IA_PD, elapsed);
 603 }
 604
 605
 606 uint32_t odhcp6c_elapsed(void)
 607 {
 608         return odhcp6c_get_milli_time() / 1000 - last_update;
 609 }
 610
 611
 612 void odhcp6c_random(void *buf, size_t len)
 613 {
 614         read(urandom_fd, buf, len);
 615 }
 616
 617 bool odhcp6c_is_bound(void)
 618 {
 619         return bound;
 620 }
 621
 622 static void sighandler(int signal)
 623 {
 624         if (signal == SIGCHLD)
 625                 while (waitpid(-1, NULL, WNOHANG) > 0);
 626         else if (signal == SIGUSR1)
 627                 do_signal = SIGUSR1;
 628         else if (signal == SIGUSR2)
 629                 do_signal = SIGUSR2;
 630         else if (signal == SIGIO)
 631                 do_signal = SIGIO;
 632         else
 633                 do_signal = SIGTERM;
 634 }