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
  36 static void sighandler(int signal);
  37 static int usage(void);
  38
  39 static uint8_t *state_data[_STATE_MAX] = {NULL};
  40 static size_t state_len[_STATE_MAX] = {0};
  41
  42 static volatile int do_signal = 0;
  43 static int urandom_fd = -1, allow_slaac_only = 0;
  44 static bool bound = false, release = true;
  45 static time_t last_update = 0;
  46
  47
  48 int main(_unused int argc, char* const argv[])
  49 {
  50         // Allocate ressources
  51         const char *pidfile = NULL;
  52         const char *script = "/usr/sbin/odhcp6c-update";
  53         ssize_t l;
  54         uint8_t buf[134];
  55         char *optpos;
  56         uint16_t opttype;
  57         enum odhcp6c_ia_mode ia_na_mode = IA_MODE_TRY;
  58         enum odhcp6c_ia_mode ia_pd_mode = IA_MODE_TRY;
  59         static struct in6_addr ifid = IN6ADDR_ANY_INIT;
  60         int sol_timeout = 120;
  61
  62         bool help = false, daemonize = false;
  63         int logopt = LOG_PID;
  64         int c, request_pd = 0;
  65         while ((c = getopt(argc, argv, "S::N:P:Fc:i:r:s:kt:hedp:")) != -1) {
  66                 switch (c) {
  67                 case 'S':
  68                         allow_slaac_only = (optarg) ? atoi(optarg) : -1;
  69                         break;
  70
  71                 case 'N':
  72                         if (!strcmp(optarg, "force")) {
  73                                 ia_na_mode = IA_MODE_FORCE;
  74                                 allow_slaac_only = -1;
  75                         } else if (!strcmp(optarg, "none")) {
  76                                 ia_na_mode = IA_MODE_NONE;
  77                         } else if (!strcmp(optarg, "try")) {
  78                                 ia_na_mode = IA_MODE_TRY;
  79                         } else{
  80                                 help = true;
  81                         }
  82                         break;
  83
  84                 case 'P':
  85                         if (allow_slaac_only >= 0 && allow_slaac_only < 10)
  86                                 allow_slaac_only = 10;
  87
  88                         request_pd = strtoul(optarg, NULL, 10);
  89                         if (request_pd == 0)
  90                                 request_pd = -1;
  91
  92                         ia_pd_mode = IA_MODE_TRY;
  93                         break;
  94
  95                 case 'F':
  96                         allow_slaac_only = -1;
  97                         ia_pd_mode = IA_MODE_FORCE;
  98                         break;
  99
 100                 case 'c':
 101                         l = script_unhexlify(&buf[4], sizeof(buf) - 4, optarg);
 102                         if (l > 0) {
 103                                 buf[0] = 0;
 104                                 buf[1] = DHCPV6_OPT_CLIENTID;
 105                                 buf[2] = 0;
 106                                 buf[3] = l;
 107                                 odhcp6c_add_state(STATE_CLIENT_ID, buf, l + 4);
 108                         } else {
 109                                 help = true;
 110                         }
 111                         break;
 112
 113                 case 'i':
 114                         if (inet_pton(AF_INET6, optarg, &ifid) != 1)
 115                                 help = true;
 116                         break;
 117
 118                 case 'r':
 119                         optpos = optarg;
 120                         while (optpos[0]) {
 121                                 opttype = htons(strtoul(optarg, &optpos, 10));
 122                                 if (optpos == optarg)
 123                                         break;
 124                                 else if (optpos[0])
 125                                         optarg = &optpos[1];
 126                                 odhcp6c_add_state(STATE_ORO, &opttype, 2);
 127                         }
 128                         break;
 129
 130                 case 's':
 131                         script = optarg;
 132                         break;
 133
 134                 case 'k':
 135                         release = false;
 136                         break;
 137
 138                 case 't':
 139                         sol_timeout = atoi(optarg);
 140                         break;
 141
 142                 case 'e':
 143                         logopt |= LOG_PERROR;
 144                         break;
 145
 146                 case 'd':
 147                         daemonize = true;
 148                         break;
 149
 150                 case 'p':
 151                         pidfile = optarg;
 152                         break;
 153
 154                 default:
 155                         help = true;
 156                         break;
 157                 }
 158         }
 159
 160         openlog("odhcp6c", logopt, LOG_DAEMON);
 161         const char *ifname = argv[optind];
 162
 163         if (help || !ifname)
 164                 return usage();
 165
 166         signal(SIGIO, sighandler);
 167         signal(SIGHUP, sighandler);
 168         signal(SIGINT, sighandler);
 169         signal(SIGCHLD, sighandler);
 170         signal(SIGTERM, sighandler);
 171         signal(SIGUSR1, sighandler);
 172         signal(SIGUSR2, sighandler);
 173
 174         if ((urandom_fd = open("/dev/urandom", O_CLOEXEC | O_RDONLY)) < 0 ||
 175                         init_dhcpv6(ifname, request_pd, sol_timeout) ||
 176                         ra_init(ifname, &ifid) || script_init(script, ifname)) {
 177                 syslog(LOG_ERR, "failed to initialize: %s", strerror(errno));
 178                 return 3;
 179         }
 180
 181         if (daemonize) {
 182                 openlog("odhcp6c", LOG_PID, LOG_DAEMON); // Disable LOG_PERROR
 183                 if (daemon(0, 0)) {
 184                         syslog(LOG_ERR, "Failed to daemonize: %s",
 185                                         strerror(errno));
 186                         return 4;
 187                 }
 188
 189                 char pidbuf[128];
 190                 if (!pidfile) {
 191                         snprintf(pidbuf, sizeof(pidbuf),
 192                                         "/var/run/odhcp6c.%s.pid", ifname);
 193                         pidfile = pidbuf;
 194                 }
 195
 196                 int fd = open(pidfile, O_WRONLY | O_CREAT);
 197                 if (fd >= 0) {
 198                         char buf[8];
 199                         int len = snprintf(buf, sizeof(buf), "%i\n", getpid());
 200                         write(fd, buf, len);
 201                         close(fd);
 202                 }
 203         }
 204
 205         script_call("started");
 206
 207         while (do_signal != SIGTERM) { // Main logic
 208                 odhcp6c_clear_state(STATE_SERVER_ID);
 209                 odhcp6c_clear_state(STATE_IA_NA);
 210                 odhcp6c_clear_state(STATE_IA_PD);
 211                 odhcp6c_clear_state(STATE_SNTP_IP);
 212                 odhcp6c_clear_state(STATE_SNTP_FQDN);
 213                 odhcp6c_clear_state(STATE_SIP_IP);
 214                 odhcp6c_clear_state(STATE_SIP_FQDN);
 215                 dhcpv6_set_ia_mode(ia_na_mode, ia_pd_mode);
 216                 bound = false;
 217
 218                 // Server candidates need deep-delete
 219                 size_t cand_len;
 220                 struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
 221                 for (size_t i = 0; i < cand_len / sizeof(*cand); ++i) {
 222                         free(cand[i].ia_na);
 223                         free(cand[i].ia_pd);
 224                 }
 225                 odhcp6c_clear_state(STATE_SERVER_CAND);
 226
 227                 syslog(LOG_NOTICE, "(re)starting transaction on %s", ifname);
 228
 229                 do_signal = 0;
 230                 int res = dhcpv6_request(DHCPV6_MSG_SOLICIT);
 231                 odhcp6c_signal_process();
 232
 233                 if (res <= 0) {
 234                         continue; // Might happen if we got a signal
 235                 } else if (res == DHCPV6_STATELESS) { // Stateless mode
 236                         while (do_signal == 0 || do_signal == SIGUSR1) {
 237                                 do_signal = 0;
 238
 239                                 res = dhcpv6_request(DHCPV6_MSG_INFO_REQ);
 240                                 odhcp6c_signal_process();
 241                                 if (do_signal == SIGUSR1)
 242                                         continue;
 243                                 else if (res < 0)
 244                                         break;
 245                                 else if (res > 0)
 246                                         script_call("informed");
 247
 248                                 bound = true;
 249                                 syslog(LOG_NOTICE, "entering stateless-mode on %s", ifname);
 250
 251                                 if (dhcpv6_poll_reconfigure() > 0)
 252                                         script_call("informed");
 253                         }
 254
 255                         continue;
 256                 }
 257
 258                 // Stateful mode
 259                 if (dhcpv6_request(DHCPV6_MSG_REQUEST) <= 0)
 260                         continue;
 261
 262                 odhcp6c_signal_process();
 263                 script_call("bound");
 264                 bound = true;
 265                 syslog(LOG_NOTICE, "entering stateful-mode on %s", ifname);
 266
 267                 while (do_signal == 0 || do_signal == SIGUSR1) {
 268                         // Renew Cycle
 269                         // Wait for T1 to expire or until we get a reconfigure
 270                         int res = dhcpv6_poll_reconfigure();
 271                         odhcp6c_signal_process();
 272                         if (res > 0) {
 273                                 script_call("updated");
 274                                 continue;
 275                         }
 276
 277                         // Handle signal, if necessary
 278                         if (do_signal == SIGUSR1)
 279                                 do_signal = 0; // Acknowledged
 280                         else if (do_signal > 0)
 281                                 break; // Other signal type
 282
 283                         size_t ia_pd_len, ia_na_len, ia_pd_new, ia_na_new;
 284                         odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 285                         odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 286
 287                         // If we have any IAs, send renew, otherwise request
 288                         int r;
 289                         if (ia_pd_len == 0 && ia_na_len == 0)
 290                                 r = dhcpv6_request(DHCPV6_MSG_REQUEST);
 291                         else
 292                                 r = dhcpv6_request(DHCPV6_MSG_RENEW);
 293                         odhcp6c_signal_process();
 294                         if (r > 0) { // Renew was succesfull
 295                                 // Publish updates
 296                                 script_call("updated");
 297                                 continue; // Renew was successful
 298                         }
 299
 300                         odhcp6c_clear_state(STATE_SERVER_ID); // Remove binding
 301
 302                         // If we have IAs, try rebind otherwise restart
 303                         res = dhcpv6_request(DHCPV6_MSG_REBIND);
 304                         odhcp6c_signal_process();
 305
 306                         odhcp6c_get_state(STATE_IA_PD, &ia_pd_new);
 307                         odhcp6c_get_state(STATE_IA_NA, &ia_na_new);
 308                         if (res <= 0 || (ia_pd_new == 0 && ia_pd_len) ||
 309                                         (ia_na_new == 0 && ia_na_len))
 310                                 break; // We lost all our IAs, restart
 311                         else if (res > 0)
 312                                 script_call("rebound");
 313                 }
 314
 315
 316                 size_t ia_pd_len, ia_na_len, server_id_len;
 317                 odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 318                 odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 319                 odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 320
 321                 // Add all prefixes to lost prefixes
 322                 bound = false;
 323                 script_call("unbound");
 324
 325                 if (server_id_len > 0 && (ia_pd_len > 0 || ia_na_len > 0) && release)
 326                         dhcpv6_request(DHCPV6_MSG_RELEASE);
 327
 328                 odhcp6c_clear_state(STATE_IA_NA);
 329                 odhcp6c_clear_state(STATE_IA_PD);
 330         }
 331
 332         script_call("stopped");
 333         return 0;
 334 }
 335
 336
 337 static int usage(void)
 338 {
 339         const char buf[] =
 340         "Usage: odhcp6c [options] <interface>\n"
 341         "\nFeature options:\n"
 342         "       -S <time>       Wait at least <time> sec for a DHCP-server (0)\n"
 343         "       -N <mode>       Mode for requesting addresses [try|force|none]\n"
 344         "       -P <length>     Request IPv6-Prefix (0 = auto)\n"
 345         "       -F              Force IPv6-Prefix\n"
 346         "       -c <clientid>   Override client-ID (base-16 encoded)\n"
 347         "       -i <iface-id>   Use a custom interface identifier for RA handling\n"
 348         "       -r <options>    Options to be requested (comma-separated)\n"
 349         "       -s <script>     Status update script (/usr/sbin/odhcp6c-update)\n"
 350         "       -k              Don't send a RELEASE when stopping\n"
 351         "       -t <seconds>    Maximum timeout for DHCPv6-SOLICIT (120)\n"
 352         "\nInvocation options:\n"
 353         "       -p <pidfile>    Set pidfile (/var/run/6relayd.pid)\n"
 354         "       -d              Daemonize\n"
 355         "       -e              Write logmessages to stderr\n"
 356         //"     -v              Increase logging verbosity\n"
 357         "       -h              Show this help\n\n";
 358         write(STDERR_FILENO, buf, sizeof(buf));
 359         return 1;
 360 }
 361
 362
 363 // Don't want to pull-in librt and libpthread just for a monotonic clock...
 364 uint64_t odhcp6c_get_milli_time(void)
 365 {
 366         struct timespec t = {0, 0};
 367         syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &t);
 368         return t.tv_sec * 1000 + t.tv_nsec / 1000000;
 369 }
 370
 371
 372 static uint8_t* odhcp6c_resize_state(enum odhcp6c_state state, ssize_t len)
 373 {
 374         if (len == 0)
 375                 return state_data[state] + state_len[state];
 376         else if (state_len[state] + len > 1024)
 377                 return NULL;
 378
 379         uint8_t *n = realloc(state_data[state], state_len[state] + len);
 380         if (n || state_len[state] + len == 0) {
 381                 state_data[state] = n;
 382                 n += state_len[state];
 383                 state_len[state] += len;
 384         }
 385         return n;
 386 }
 387
 388
 389 bool odhcp6c_signal_process(void)
 390 {
 391         if (do_signal == SIGIO) {
 392                 do_signal = 0;
 393                 bool ra_updated = ra_process();
 394
 395                 if (ra_updated && (bound || allow_slaac_only == 0))
 396                         script_call("ra-updated"); // Immediate process urgent events
 397                 else if (ra_updated && !bound && allow_slaac_only > 0)
 398                         script_delay_call("ra-updated", allow_slaac_only);
 399         }
 400
 401         return do_signal != 0;
 402 }
 403
 404
 405 void odhcp6c_clear_state(enum odhcp6c_state state)
 406 {
 407         state_len[state] = 0;
 408 }
 409
 410
 411 void odhcp6c_add_state(enum odhcp6c_state state, const void *data, size_t len)
 412 {
 413         uint8_t *n = odhcp6c_resize_state(state, len);
 414         if (n)
 415                 memcpy(n, data, len);
 416 }
 417
 418
 419 size_t odhcp6c_remove_state(enum odhcp6c_state state, size_t offset, size_t len)
 420 {
 421         uint8_t *data = state_data[state];
 422         ssize_t len_after = state_len[state] - (offset + len);
 423         if (len_after < 0)
 424                 return state_len[state];
 425
 426         memmove(data + offset, data + offset + len, len_after);
 427         return state_len[state] -= len;
 428 }
 429
 430
 431 void* odhcp6c_move_state(enum odhcp6c_state state, size_t *len)
 432 {
 433         *len = state_len[state];
 434         void *data = state_data[state];
 435
 436         state_len[state] = 0;
 437         state_data[state] = NULL;
 438
 439         return data;
 440 }
 441
 442
 443 void* odhcp6c_get_state(enum odhcp6c_state state, size_t *len)
 444 {
 445         *len = state_len[state];
 446         return state_data[state];
 447 }
 448
 449
 450 struct odhcp6c_entry* odhcp6c_find_entry(enum odhcp6c_state state, const struct odhcp6c_entry *new)
 451 {
 452         size_t len, cmplen = offsetof(struct odhcp6c_entry, target) + new->length / 8;
 453         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 454         struct odhcp6c_entry *x = NULL;
 455
 456         for (struct odhcp6c_entry *c = start; !x && c < &start[len/sizeof(*c)]; ++c)
 457                 if (!memcmp(c, new, cmplen))
 458                         return c;
 459
 460         return NULL;
 461 }
 462
 463
 464 bool odhcp6c_update_entry_safe(enum odhcp6c_state state, struct odhcp6c_entry *new, uint32_t safe)
 465 {
 466         size_t len;
 467         struct odhcp6c_entry *x = odhcp6c_find_entry(state, new);
 468         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 469         bool changed = true;
 470
 471         if (x && x->valid > new->valid && new->valid < safe)
 472                 new->valid = safe;
 473
 474         if (new->valid > 0) {
 475                 if (x) {
 476                         if (new->valid >= x->valid && new->valid - x->valid < 60 &&
 477                                         new->preferred >= x->preferred &&
 478                                         new->preferred - x->preferred < 60 &&
 479                                         x->class == new->class)
 480                                 changed = false;
 481                         x->valid = new->valid;
 482                         x->preferred = new->preferred;
 483                         x->t1 = new->t1;
 484                         x->t2 = new->t2;
 485                         x->class = new->class;
 486                 } else {
 487                         odhcp6c_add_state(state, new, sizeof(*new));
 488                 }
 489         } else if (x) {
 490                 odhcp6c_remove_state(state, (x - start) * sizeof(*x), sizeof(*x));
 491         }
 492         return changed;
 493 }
 494
 495
 496 bool odhcp6c_update_entry(enum odhcp6c_state state, struct odhcp6c_entry *new)
 497 {
 498         return odhcp6c_update_entry_safe(state, new, 0);
 499 }
 500
 501
 502 static void odhcp6c_expire_list(enum odhcp6c_state state, uint32_t elapsed)
 503 {
 504         size_t len;
 505         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 506         for (struct odhcp6c_entry *c = start; c < &start[len / sizeof(*c)]; ++c) {
 507                 if (c->t1 < elapsed)
 508                         c->t1 = 0;
 509                 else if (c->t1 != UINT32_MAX)
 510                         c->t1 -= elapsed;
 511
 512                 if (c->t2 < elapsed)
 513                         c->t2 = 0;
 514                 else if (c->t2 != UINT32_MAX)
 515                         c->t2 -= elapsed;
 516
 517                 if (c->preferred < elapsed)
 518                         c->preferred = 0;
 519                 else if (c->preferred != UINT32_MAX)
 520                         c->preferred -= elapsed;
 521
 522                 if (c->valid < elapsed)
 523                         c->valid = 0;
 524                 else if (c->valid != UINT32_MAX)
 525                         c->valid -= elapsed;
 526
 527                 if (!c->valid)
 528                         odhcp6c_remove_state(state, (c - start) * sizeof(*c), sizeof(*c));
 529         }
 530 }
 531
 532
 533 void odhcp6c_expire(void)
 534 {
 535         time_t now = odhcp6c_get_milli_time() / 1000;
 536         uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 537         last_update = now;
 538
 539         odhcp6c_expire_list(STATE_RA_PREFIX, elapsed);
 540         odhcp6c_expire_list(STATE_RA_ROUTE, elapsed);
 541         odhcp6c_expire_list(STATE_RA_DNS, elapsed);
 542         odhcp6c_expire_list(STATE_IA_NA, elapsed);
 543         odhcp6c_expire_list(STATE_IA_PD, elapsed);
 544 }
 545
 546
 547 uint32_t odhcp6c_elapsed(void)
 548 {
 549         return odhcp6c_get_milli_time() / 1000 - last_update;
 550 }
 551
 552
 553 void odhcp6c_random(void *buf, size_t len)
 554 {
 555         read(urandom_fd, buf, len);
 556 }
 557
 558 bool odhcp6c_is_bound(void)
 559 {
 560         return bound;
 561 }
 562
 563 static void sighandler(int signal)
 564 {
 565         if (signal == SIGCHLD)
 566                 while (waitpid(-1, NULL, WNOHANG) > 0);
 567         else if (signal == SIGUSR1)
 568                 do_signal = SIGUSR1;
 569         else if (signal == SIGUSR2)
 570                 do_signal = SIGUSR2;
 571         else if (signal == SIGIO)
 572                 do_signal = SIGIO;
 573         else
 574                 do_signal = SIGTERM;
 575 }