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 = 120;
  65
  66         bool help = false, daemonize = false;
  67         int logopt = LOG_PID;
  68         int c, request_pd = 0;
  69         while ((c = getopt(argc, argv, "S::N:P:Fc:i:r:s:kt:hedp:")) != -1) {
  70                 switch (c) {
  71                 case 'S':
  72                         allow_slaac_only = (optarg) ? atoi(optarg) : -1;
  73                         break;
  74
  75                 case 'N':
  76                         if (!strcmp(optarg, "force")) {
  77                                 ia_na_mode = IA_MODE_FORCE;
  78                                 allow_slaac_only = -1;
  79                         } else if (!strcmp(optarg, "none")) {
  80                                 ia_na_mode = IA_MODE_NONE;
  81                         } else if (!strcmp(optarg, "try")) {
  82                                 ia_na_mode = IA_MODE_TRY;
  83                         } else{
  84                                 help = true;
  85                         }
  86                         break;
  87
  88                 case 'P':
  89                         if (allow_slaac_only >= 0 && allow_slaac_only < 10)
  90                                 allow_slaac_only = 10;
  91
  92                         request_pd = strtoul(optarg, NULL, 10);
  93                         if (request_pd == 0)
  94                                 request_pd = -1;
  95
  96                         break;
  97
  98                 case 'F':
  99                         allow_slaac_only = -1;
 100                         ia_pd_mode = IA_MODE_FORCE;
 101                         break;
 102
 103                 case 'c':
 104                         l = script_unhexlify(&buf[4], sizeof(buf) - 4, optarg);
 105                         if (l > 0) {
 106                                 buf[0] = 0;
 107                                 buf[1] = DHCPV6_OPT_CLIENTID;
 108                                 buf[2] = 0;
 109                                 buf[3] = l;
 110                                 odhcp6c_add_state(STATE_CLIENT_ID, buf, l + 4);
 111                         } else {
 112                                 help = true;
 113                         }
 114                         break;
 115
 116                 case 'i':
 117                         if (inet_pton(AF_INET6, optarg, &ifid) != 1)
 118                                 help = true;
 119                         break;
 120
 121                 case 'r':
 122                         optpos = optarg;
 123                         while (optpos[0]) {
 124                                 opttype = htons(strtoul(optarg, &optpos, 10));
 125                                 if (optpos == optarg)
 126                                         break;
 127                                 else if (optpos[0])
 128                                         optarg = &optpos[1];
 129                                 odhcp6c_add_state(STATE_ORO, &opttype, 2);
 130                         }
 131                         break;
 132
 133                 case 's':
 134                         script = optarg;
 135                         break;
 136
 137                 case 'k':
 138                         release = false;
 139                         break;
 140
 141                 case 't':
 142                         sol_timeout = atoi(optarg);
 143                         break;
 144
 145                 case 'e':
 146                         logopt |= LOG_PERROR;
 147                         break;
 148
 149                 case 'd':
 150                         daemonize = true;
 151                         break;
 152
 153                 case 'p':
 154                         pidfile = optarg;
 155                         break;
 156
 157                 default:
 158                         help = true;
 159                         break;
 160                 }
 161         }
 162
 163         openlog("odhcp6c", logopt, LOG_DAEMON);
 164         const char *ifname = argv[optind];
 165
 166         if (help || !ifname)
 167                 return usage();
 168
 169         signal(SIGIO, sighandler);
 170         signal(SIGHUP, sighandler);
 171         signal(SIGINT, sighandler);
 172         signal(SIGCHLD, sighandler);
 173         signal(SIGTERM, sighandler);
 174         signal(SIGUSR1, sighandler);
 175         signal(SIGUSR2, sighandler);
 176
 177         if ((urandom_fd = open("/dev/urandom", O_CLOEXEC | O_RDONLY)) < 0 ||
 178                         init_dhcpv6(ifname, request_pd, sol_timeout) ||
 179                         ra_init(ifname, &ifid) || script_init(script, ifname)) {
 180                 syslog(LOG_ERR, "failed to initialize: %s", strerror(errno));
 181                 return 3;
 182         }
 183
 184         if (daemonize) {
 185                 openlog("odhcp6c", LOG_PID, LOG_DAEMON); // Disable LOG_PERROR
 186                 if (daemon(0, 0)) {
 187                         syslog(LOG_ERR, "Failed to daemonize: %s",
 188                                         strerror(errno));
 189                         return 4;
 190                 }
 191
 192                 char pidbuf[128];
 193                 if (!pidfile) {
 194                         snprintf(pidbuf, sizeof(pidbuf),
 195                                         "/var/run/odhcp6c.%s.pid", ifname);
 196                         pidfile = pidbuf;
 197                 }
 198
 199                 int fd = open(pidfile, O_WRONLY | O_CREAT);
 200                 if (fd >= 0) {
 201                         char buf[8];
 202                         int len = snprintf(buf, sizeof(buf), "%i\n", getpid());
 203                         write(fd, buf, len);
 204                         close(fd);
 205                 }
 206         }
 207
 208         script_call("started");
 209
 210         while (do_signal != SIGTERM) { // Main logic
 211                 odhcp6c_clear_state(STATE_SERVER_ID);
 212                 odhcp6c_clear_state(STATE_IA_NA);
 213                 odhcp6c_clear_state(STATE_IA_PD);
 214                 odhcp6c_clear_state(STATE_SNTP_IP);
 215                 odhcp6c_clear_state(STATE_SNTP_FQDN);
 216                 odhcp6c_clear_state(STATE_SIP_IP);
 217                 odhcp6c_clear_state(STATE_SIP_FQDN);
 218                 dhcpv6_set_ia_mode(ia_na_mode, ia_pd_mode);
 219                 bound = false;
 220
 221                 // Server candidates need deep-delete
 222                 size_t cand_len;
 223                 struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
 224                 for (size_t i = 0; i < cand_len / sizeof(*cand); ++i) {
 225                         free(cand[i].ia_na);
 226                         free(cand[i].ia_pd);
 227                 }
 228                 odhcp6c_clear_state(STATE_SERVER_CAND);
 229
 230                 syslog(LOG_NOTICE, "(re)starting transaction on %s", ifname);
 231
 232                 do_signal = 0;
 233                 int res = dhcpv6_request(DHCPV6_MSG_SOLICIT);
 234                 odhcp6c_signal_process();
 235
 236                 if (res <= 0) {
 237                         continue; // Might happen if we got a signal
 238                 } else if (res == DHCPV6_STATELESS) { // Stateless mode
 239                         while (do_signal == 0 || do_signal == SIGUSR1) {
 240                                 do_signal = 0;
 241
 242                                 res = dhcpv6_request(DHCPV6_MSG_INFO_REQ);
 243                                 odhcp6c_signal_process();
 244                                 if (do_signal == SIGUSR1)
 245                                         continue;
 246                                 else if (res < 0)
 247                                         break;
 248                                 else if (res > 0)
 249                                         script_call("informed");
 250
 251                                 bound = true;
 252                                 syslog(LOG_NOTICE, "entering stateless-mode on %s", ifname);
 253
 254                                 if (dhcpv6_poll_reconfigure() > 0)
 255                                         script_call("informed");
 256                         }
 257
 258                         continue;
 259                 }
 260
 261                 // Stateful mode
 262                 if (dhcpv6_request(DHCPV6_MSG_REQUEST) <= 0)
 263                         continue;
 264
 265                 odhcp6c_signal_process();
 266                 script_call("bound");
 267                 bound = true;
 268                 syslog(LOG_NOTICE, "entering stateful-mode on %s", ifname);
 269 #ifdef EXT_BFD_PING
 270                 bfd_start(ifname, 3, 10);
 271 #endif
 272
 273                 while (do_signal == 0 || do_signal == SIGUSR1) {
 274                         // Renew Cycle
 275                         // Wait for T1 to expire or until we get a reconfigure
 276                         int res = dhcpv6_poll_reconfigure();
 277                         odhcp6c_signal_process();
 278                         if (res > 0) {
 279                                 script_call("updated");
 280                                 continue;
 281                         }
 282
 283                         // Handle signal, if necessary
 284                         if (do_signal == SIGUSR1)
 285                                 do_signal = 0; // Acknowledged
 286                         else if (do_signal > 0)
 287                                 break; // Other signal type
 288
 289                         size_t ia_pd_len, ia_na_len, ia_pd_new, ia_na_new;
 290                         odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 291                         odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 292
 293                         // If we have any IAs, send renew, otherwise request
 294                         int r;
 295                         if (ia_pd_len == 0 && ia_na_len == 0)
 296                                 r = dhcpv6_request(DHCPV6_MSG_REQUEST);
 297                         else
 298                                 r = dhcpv6_request(DHCPV6_MSG_RENEW);
 299                         odhcp6c_signal_process();
 300                         if (r > 0) { // Renew was succesfull
 301                                 // Publish updates
 302                                 script_call("updated");
 303                                 continue; // Renew was successful
 304                         }
 305
 306                         odhcp6c_clear_state(STATE_SERVER_ID); // Remove binding
 307
 308                         // If we have IAs, try rebind otherwise restart
 309                         res = dhcpv6_request(DHCPV6_MSG_REBIND);
 310                         odhcp6c_signal_process();
 311
 312                         odhcp6c_get_state(STATE_IA_PD, &ia_pd_new);
 313                         odhcp6c_get_state(STATE_IA_NA, &ia_na_new);
 314                         if (res <= 0 || (ia_pd_new == 0 && ia_pd_len) ||
 315                                         (ia_na_new == 0 && ia_na_len))
 316                                 break; // We lost all our IAs, restart
 317                         else if (res > 0)
 318                                 script_call("rebound");
 319                 }
 320
 321 #ifdef EXT_BFD_PING
 322                 bfd_stop();
 323 #endif
 324
 325
 326                 size_t ia_pd_len, ia_na_len, server_id_len;
 327                 odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 328                 odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 329                 odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 330
 331                 // Add all prefixes to lost prefixes
 332                 bound = false;
 333                 script_call("unbound");
 334
 335                 if (server_id_len > 0 && (ia_pd_len > 0 || ia_na_len > 0) && release)
 336                         dhcpv6_request(DHCPV6_MSG_RELEASE);
 337
 338                 odhcp6c_clear_state(STATE_IA_NA);
 339                 odhcp6c_clear_state(STATE_IA_PD);
 340         }
 341
 342         script_call("stopped");
 343         return 0;
 344 }
 345
 346
 347 static int usage(void)
 348 {
 349         const char buf[] =
 350         "Usage: odhcp6c [options] <interface>\n"
 351         "\nFeature options:\n"
 352         "       -S <time>       Wait at least <time> sec for a DHCP-server (0)\n"
 353         "       -N <mode>       Mode for requesting addresses [try|force|none]\n"
 354         "       -P <length>     Request IPv6-Prefix (0 = auto)\n"
 355         "       -F              Force IPv6-Prefix\n"
 356         "       -c <clientid>   Override client-ID (base-16 encoded)\n"
 357         "       -i <iface-id>   Use a custom interface identifier for RA handling\n"
 358         "       -r <options>    Options to be requested (comma-separated)\n"
 359         "       -s <script>     Status update script (/usr/sbin/odhcp6c-update)\n"
 360         "       -k              Don't send a RELEASE when stopping\n"
 361         "       -t <seconds>    Maximum timeout for DHCPv6-SOLICIT (120)\n"
 362         "\nInvocation options:\n"
 363         "       -p <pidfile>    Set pidfile (/var/run/6relayd.pid)\n"
 364         "       -d              Daemonize\n"
 365         "       -e              Write logmessages to stderr\n"
 366         //"     -v              Increase logging verbosity\n"
 367         "       -h              Show this help\n\n";
 368         write(STDERR_FILENO, buf, sizeof(buf));
 369         return 1;
 370 }
 371
 372
 373 // Don't want to pull-in librt and libpthread just for a monotonic clock...
 374 uint64_t odhcp6c_get_milli_time(void)
 375 {
 376         struct timespec t = {0, 0};
 377         syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &t);
 378         return t.tv_sec * 1000 + t.tv_nsec / 1000000;
 379 }
 380
 381
 382 static uint8_t* odhcp6c_resize_state(enum odhcp6c_state state, ssize_t len)
 383 {
 384         if (len == 0)
 385                 return state_data[state] + state_len[state];
 386         else if (state_len[state] + len > 1024)
 387                 return NULL;
 388
 389         uint8_t *n = realloc(state_data[state], state_len[state] + len);
 390         if (n || state_len[state] + len == 0) {
 391                 state_data[state] = n;
 392                 n += state_len[state];
 393                 state_len[state] += len;
 394         }
 395         return n;
 396 }
 397
 398
 399 bool odhcp6c_signal_process(void)
 400 {
 401         if (do_signal == SIGIO) {
 402                 do_signal = 0;
 403                 bool ra_updated = ra_process();
 404
 405                 if (ra_link_up())
 406                         do_signal = SIGUSR2;
 407
 408                 if (ra_updated && (bound || allow_slaac_only == 0))
 409                         script_call("ra-updated"); // Immediate process urgent events
 410                 else if (ra_updated && !bound && allow_slaac_only > 0)
 411                         script_delay_call("ra-updated", allow_slaac_only);
 412
 413 #ifdef EXT_BFD_PING
 414                 bfd_receive();
 415 #endif
 416         }
 417
 418         return do_signal != 0;
 419 }
 420
 421
 422 void odhcp6c_clear_state(enum odhcp6c_state state)
 423 {
 424         state_len[state] = 0;
 425 }
 426
 427
 428 void odhcp6c_add_state(enum odhcp6c_state state, const void *data, size_t len)
 429 {
 430         uint8_t *n = odhcp6c_resize_state(state, len);
 431         if (n)
 432                 memcpy(n, data, len);
 433 }
 434
 435
 436 size_t odhcp6c_remove_state(enum odhcp6c_state state, size_t offset, size_t len)
 437 {
 438         uint8_t *data = state_data[state];
 439         ssize_t len_after = state_len[state] - (offset + len);
 440         if (len_after < 0)
 441                 return state_len[state];
 442
 443         memmove(data + offset, data + offset + len, len_after);
 444         return state_len[state] -= len;
 445 }
 446
 447
 448 void* odhcp6c_move_state(enum odhcp6c_state state, size_t *len)
 449 {
 450         *len = state_len[state];
 451         void *data = state_data[state];
 452
 453         state_len[state] = 0;
 454         state_data[state] = NULL;
 455
 456         return data;
 457 }
 458
 459
 460 void* odhcp6c_get_state(enum odhcp6c_state state, size_t *len)
 461 {
 462         *len = state_len[state];
 463         return state_data[state];
 464 }
 465
 466
 467 struct odhcp6c_entry* odhcp6c_find_entry(enum odhcp6c_state state, const struct odhcp6c_entry *new)
 468 {
 469         size_t len, cmplen = offsetof(struct odhcp6c_entry, target) + new->length / 8;
 470         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 471         struct odhcp6c_entry *x = NULL;
 472
 473         for (struct odhcp6c_entry *c = start; !x && c < &start[len/sizeof(*c)]; ++c)
 474                 if (!memcmp(c, new, cmplen))
 475                         return c;
 476
 477         return NULL;
 478 }
 479
 480
 481 bool odhcp6c_update_entry_safe(enum odhcp6c_state state, struct odhcp6c_entry *new, uint32_t safe)
 482 {
 483         size_t len;
 484         struct odhcp6c_entry *x = odhcp6c_find_entry(state, new);
 485         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 486
 487         if (x && x->valid > new->valid && new->valid < safe)
 488                 new->valid = safe;
 489
 490         if (new->valid > 0) {
 491                 if (x) {
 492                         if (new->valid >= x->valid && new->valid - x->valid < 60 &&
 493                                         new->preferred >= x->preferred &&
 494                                         new->preferred - x->preferred < 60 &&
 495                                         x->class == new->class)
 496                                 return false;
 497                         x->valid = new->valid;
 498                         x->preferred = new->preferred;
 499                         x->t1 = new->t1;
 500                         x->t2 = new->t2;
 501                         x->class = new->class;
 502                 } else {
 503                         odhcp6c_add_state(state, new, sizeof(*new));
 504                 }
 505         } else if (x) {
 506                 odhcp6c_remove_state(state, (x - start) * sizeof(*x), sizeof(*x));
 507         }
 508         return true;
 509 }
 510
 511
 512 bool odhcp6c_update_entry(enum odhcp6c_state state, struct odhcp6c_entry *new)
 513 {
 514         return odhcp6c_update_entry_safe(state, new, 0);
 515 }
 516
 517
 518 static void odhcp6c_expire_list(enum odhcp6c_state state, uint32_t elapsed)
 519 {
 520         size_t len;
 521         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 522         for (struct odhcp6c_entry *c = start; c < &start[len / sizeof(*c)]; ++c) {
 523                 if (c->t1 < elapsed)
 524                         c->t1 = 0;
 525                 else if (c->t1 != UINT32_MAX)
 526                         c->t1 -= elapsed;
 527
 528                 if (c->t2 < elapsed)
 529                         c->t2 = 0;
 530                 else if (c->t2 != UINT32_MAX)
 531                         c->t2 -= elapsed;
 532
 533                 if (c->preferred < elapsed)
 534                         c->preferred = 0;
 535                 else if (c->preferred != UINT32_MAX)
 536                         c->preferred -= elapsed;
 537
 538                 if (c->valid < elapsed)
 539                         c->valid = 0;
 540                 else if (c->valid != UINT32_MAX)
 541                         c->valid -= elapsed;
 542
 543                 if (!c->valid)
 544                         odhcp6c_remove_state(state, (c - start) * sizeof(*c), sizeof(*c));
 545         }
 546 }
 547
 548
 549 void odhcp6c_expire(void)
 550 {
 551         time_t now = odhcp6c_get_milli_time() / 1000;
 552         uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 553         last_update = now;
 554
 555         odhcp6c_expire_list(STATE_RA_PREFIX, elapsed);
 556         odhcp6c_expire_list(STATE_RA_ROUTE, elapsed);
 557         odhcp6c_expire_list(STATE_RA_DNS, elapsed);
 558         odhcp6c_expire_list(STATE_IA_NA, elapsed);
 559         odhcp6c_expire_list(STATE_IA_PD, elapsed);
 560 }
 561
 562
 563 uint32_t odhcp6c_elapsed(void)
 564 {
 565         return odhcp6c_get_milli_time() / 1000 - last_update;
 566 }
 567
 568
 569 void odhcp6c_random(void *buf, size_t len)
 570 {
 571         read(urandom_fd, buf, len);
 572 }
 573
 574 bool odhcp6c_is_bound(void)
 575 {
 576         return bound;
 577 }
 578
 579 static void sighandler(int signal)
 580 {
 581         if (signal == SIGCHLD)
 582                 while (waitpid(-1, NULL, WNOHANG) > 0);
 583         else if (signal == SIGUSR1)
 584                 do_signal = SIGUSR1;
 585         else if (signal == SIGUSR2)
 586                 do_signal = SIGUSR2;
 587         else if (signal == SIGIO)
 588                 do_signal = SIGIO;
 589         else
 590                 do_signal = SIGTERM;
 591 }