src/odhcp6c.c

   1 /**
   2  * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License v2 as published by
   6  * the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  */
  14
  15 #include <time.h>
  16 #include <errno.h>
  17 #include <fcntl.h>
  18 #include <stdio.h>
  19 #include <stdlib.h>
  20 #include <stddef.h>
  21 #include <unistd.h>
  22 #include <syslog.h>
  23 #include <signal.h>
  24 #include <string.h>
  25 #include <stdbool.h>
  26
  27 #include <net/if.h>
  28 #include <sys/wait.h>
  29 #include <sys/syscall.h>
  30 #include <arpa/inet.h>
  31
  32 #include "odhcp6c.h"
  33 #include "ra.h"
  34
  35 #ifdef EXT_BFD_PING
  36 #include "bfd.h"
  37 #endif
  38
  39
  40 static void sighandler(int signal);
  41 static int usage(void);
  42
  43 static uint8_t *state_data[_STATE_MAX] = {NULL};
  44 static size_t state_len[_STATE_MAX] = {0};
  45
  46 static volatile bool signal_io = false;
  47 static volatile bool signal_usr1 = false;
  48 static volatile bool signal_usr2 = false;
  49 static volatile bool signal_term = false;
  50
  51 static int urandom_fd = -1, allow_slaac_only = 0;
  52 static bool bound = false, release = true;
  53 static time_t last_update = 0;
  54
  55 int main(_unused int argc, char* const argv[])
  56 {
  57         // Allocate ressources
  58         const char *pidfile = NULL;
  59         const char *script = "/usr/sbin/odhcp6c-update";
  60         ssize_t l;
  61         uint8_t buf[134];
  62         char *optpos;
  63         uint16_t opttype;
  64         enum odhcp6c_ia_mode ia_na_mode = IA_MODE_TRY;
  65         enum odhcp6c_ia_mode ia_pd_mode = IA_MODE_NONE;
  66         int ia_pd_iaid_index = 0;
  67         static struct in6_addr ifid = IN6ADDR_ANY_INIT;
  68         int sol_timeout = DHCPV6_SOL_MAX_RT;
  69
  70 #ifdef EXT_BFD_PING
  71         int bfd_interval = 0, bfd_loss = 3;
  72 #endif
  73
  74         bool help = false, daemonize = false;
  75         int logopt = LOG_PID;
  76         int c;
  77         unsigned int client_options = DHCPV6_CLIENT_FQDN | DHCPV6_ACCEPT_RECONFIGURE;
  78
  79         while ((c = getopt(argc, argv, "S::N:V:P:FB:c:i:r:Rs:kt:hedp:fa")) != -1) {
  80                 switch (c) {
  81                 case 'S':
  82                         allow_slaac_only = (optarg) ? atoi(optarg) : -1;
  83                         break;
  84
  85                 case 'N':
  86                         if (!strcmp(optarg, "force")) {
  87                                 ia_na_mode = IA_MODE_FORCE;
  88                                 allow_slaac_only = -1;
  89                         } else if (!strcmp(optarg, "none")) {
  90                                 ia_na_mode = IA_MODE_NONE;
  91                         } else if (!strcmp(optarg, "try")) {
  92                                 ia_na_mode = IA_MODE_TRY;
  93                         } else{
  94                                 help = true;
  95                         }
  96                         break;
  97
  98                 case 'V':
  99                         l = script_unhexlify(buf, sizeof(buf), optarg);
 100                         if (!l)
 101                                 help=true;
 102
 103                         odhcp6c_add_state(STATE_VENDORCLASS, buf, l);
 104
 105                         break;
 106                 case 'P':
 107                         if (ia_pd_mode == IA_MODE_NONE)
 108                                 ia_pd_mode = IA_MODE_TRY;
 109
 110                         if (allow_slaac_only >= 0 && allow_slaac_only < 10)
 111                                 allow_slaac_only = 10;
 112
 113                         char *iaid_begin;
 114                         int iaid_len = 0;
 115
 116                         int prefix_length = strtoul(optarg, &iaid_begin, 10);
 117
 118                         if (*iaid_begin != '\0' && *iaid_begin != ',' && *iaid_begin != ':') {
 119                                 syslog(LOG_ERR, "invalid argument: '%s'", optarg);
 120                                 return 1;
 121                         }
 122
 123                         struct odhcp6c_request_prefix prefix = { 0, prefix_length };
 124
 125                         if (*iaid_begin == ',' && (iaid_len = strlen(iaid_begin)) > 1)
 126                                 memcpy(&prefix.iaid, iaid_begin + 1, iaid_len > 4 ? 4 : iaid_len);
 127                         else if (*iaid_begin == ':')
 128                                 prefix.iaid = htonl((uint32_t)strtoul(&iaid_begin[1], NULL, 16));
 129                         else
 130                                 prefix.iaid = htonl(++ia_pd_iaid_index);
 131
 132                         odhcp6c_add_state(STATE_IA_PD_INIT, &prefix, sizeof(prefix));
 133
 134                         break;
 135
 136                 case 'F':
 137                         allow_slaac_only = -1;
 138                         ia_pd_mode = IA_MODE_FORCE;
 139                         break;
 140
 141 #ifdef EXT_BFD_PING
 142                 case 'B':
 143                         bfd_interval = atoi(optarg);
 144                         break;
 145 #endif
 146
 147                 case 'c':
 148                         l = script_unhexlify(&buf[4], sizeof(buf) - 4, optarg);
 149                         if (l > 0) {
 150                                 buf[0] = 0;
 151                                 buf[1] = DHCPV6_OPT_CLIENTID;
 152                                 buf[2] = 0;
 153                                 buf[3] = l;
 154                                 odhcp6c_add_state(STATE_CLIENT_ID, buf, l + 4);
 155                         } else {
 156                                 help = true;
 157                         }
 158                         break;
 159
 160                 case 'i':
 161                         if (inet_pton(AF_INET6, optarg, &ifid) != 1)
 162                                 help = true;
 163                         break;
 164
 165                 case 'r':
 166                         optpos = optarg;
 167                         while (optpos[0]) {
 168                                 opttype = htons(strtoul(optarg, &optpos, 10));
 169                                 if (optpos == optarg)
 170                                         break;
 171                                 else if (optpos[0])
 172                                         optarg = &optpos[1];
 173                                 odhcp6c_add_state(STATE_ORO, &opttype, 2);
 174                         }
 175                         break;
 176
 177                 case 'R':
 178                         client_options |= DHCPV6_STRICT_OPTIONS;
 179                         break;
 180
 181                 case 's':
 182                         script = optarg;
 183                         break;
 184
 185                 case 'k':
 186                         release = false;
 187                         break;
 188
 189                 case 't':
 190                         sol_timeout = atoi(optarg);
 191                         break;
 192
 193                 case 'e':
 194                         logopt |= LOG_PERROR;
 195                         break;
 196
 197                 case 'd':
 198                         daemonize = true;
 199                         break;
 200
 201                 case 'p':
 202                         pidfile = optarg;
 203                         break;
 204
 205                 case 'f':
 206                         client_options &= ~DHCPV6_CLIENT_FQDN;
 207                         break;
 208
 209                 case 'a':
 210                         client_options &= ~DHCPV6_ACCEPT_RECONFIGURE;
 211                         break;
 212
 213                 default:
 214                         help = true;
 215                         break;
 216                 }
 217         }
 218
 219         openlog("odhcp6c", logopt, LOG_DAEMON);
 220         const char *ifname = argv[optind];
 221
 222         if (help || !ifname)
 223                 return usage();
 224
 225         signal(SIGIO, sighandler);
 226         signal(SIGHUP, sighandler);
 227         signal(SIGINT, sighandler);
 228         signal(SIGCHLD, sighandler);
 229         signal(SIGTERM, sighandler);
 230         signal(SIGUSR1, sighandler);
 231         signal(SIGUSR2, sighandler);
 232
 233         if ((urandom_fd = open("/dev/urandom", O_CLOEXEC | O_RDONLY)) < 0 ||
 234                         init_dhcpv6(ifname, client_options, sol_timeout) ||
 235                         ra_init(ifname, &ifid) || script_init(script, ifname)) {
 236                 syslog(LOG_ERR, "failed to initialize: %s", strerror(errno));
 237                 return 3;
 238         }
 239
 240         if (daemonize) {
 241                 openlog("odhcp6c", LOG_PID, LOG_DAEMON); // Disable LOG_PERROR
 242                 if (daemon(0, 0)) {
 243                         syslog(LOG_ERR, "Failed to daemonize: %s",
 244                                         strerror(errno));
 245                         return 4;
 246                 }
 247
 248                 char pidbuf[128];
 249                 if (!pidfile) {
 250                         snprintf(pidbuf, sizeof(pidbuf),
 251                                         "/var/run/odhcp6c.%s.pid", ifname);
 252                         pidfile = pidbuf;
 253                 }
 254
 255                 int fd = open(pidfile, O_WRONLY | O_CREAT);
 256                 if (fd >= 0) {
 257                         char buf[8];
 258                         int len = snprintf(buf, sizeof(buf), "%i\n", getpid());
 259                         write(fd, buf, len);
 260                         close(fd);
 261                 }
 262         }
 263
 264         script_call("started");
 265
 266         while (!signal_term) { // Main logic
 267                 odhcp6c_clear_state(STATE_SERVER_ID);
 268                 odhcp6c_clear_state(STATE_IA_NA);
 269                 odhcp6c_clear_state(STATE_IA_PD);
 270                 odhcp6c_clear_state(STATE_SNTP_IP);
 271                 odhcp6c_clear_state(STATE_NTP_IP);
 272                 odhcp6c_clear_state(STATE_NTP_FQDN);
 273                 odhcp6c_clear_state(STATE_SIP_IP);
 274                 odhcp6c_clear_state(STATE_SIP_FQDN);
 275                 dhcpv6_set_ia_mode(ia_na_mode, ia_pd_mode);
 276                 bound = false;
 277
 278                 syslog(LOG_NOTICE, "(re)starting transaction on %s", ifname);
 279
 280                 signal_usr1 = signal_usr2 = false;
 281                 int mode = dhcpv6_request(DHCPV6_MSG_SOLICIT);
 282                 odhcp6c_signal_process();
 283
 284                 if (mode < 0)
 285                         continue;
 286
 287                 do {
 288                         int res = dhcpv6_request(mode == DHCPV6_STATELESS ?
 289                                         DHCPV6_MSG_INFO_REQ : DHCPV6_MSG_REQUEST);
 290                         bool signalled = odhcp6c_signal_process();
 291
 292                         if (res > 0)
 293                                 break;
 294                         else if (signalled) {
 295                                 mode = -1;
 296                                 break;
 297                         }
 298
 299                         mode = dhcpv6_promote_server_cand();
 300                 } while (mode > DHCPV6_UNKNOWN);
 301
 302                 if (mode < 0)
 303                         continue;
 304
 305                 switch (mode) {
 306                 case DHCPV6_STATELESS:
 307                         bound = true;
 308                         syslog(LOG_NOTICE, "entering stateless-mode on %s", ifname);
 309
 310                         while (!signal_usr2 && !signal_term) {
 311                                 signal_usr1 = false;
 312                                 script_call("informed");
 313
 314                                 int res = dhcpv6_poll_reconfigure();
 315                                 odhcp6c_signal_process();
 316
 317                                 if (res > 0)
 318                                         continue;
 319
 320                                 if (signal_usr1) {
 321                                         signal_usr1 = false; // Acknowledged
 322                                         continue;
 323                                 }
 324                                 if (signal_usr2 || signal_term)
 325                                         break;
 326
 327                                 res = dhcpv6_request(DHCPV6_MSG_INFO_REQ);
 328                                 odhcp6c_signal_process();
 329                                 if (signal_usr1)
 330                                         continue;
 331                                 else if (res < 0)
 332                                         break;
 333                         }
 334                         break;
 335
 336                 case DHCPV6_STATEFUL:
 337                         script_call("bound");
 338                         bound = true;
 339                         syslog(LOG_NOTICE, "entering stateful-mode on %s", ifname);
 340 #ifdef EXT_BFD_PING
 341                         if (bfd_interval > 0)
 342                                 bfd_start(ifname, bfd_loss, bfd_interval);
 343 #endif
 344
 345                         while (!signal_usr2 && !signal_term) {
 346                                 // Renew Cycle
 347                                 // Wait for T1 to expire or until we get a reconfigure
 348                                 int res = dhcpv6_poll_reconfigure();
 349                                 odhcp6c_signal_process();
 350                                 if (res > 0) {
 351                                         script_call("updated");
 352                                         continue;
 353                                 }
 354
 355                                 // Handle signal, if necessary
 356                                 if (signal_usr1)
 357                                         signal_usr1 = false; // Acknowledged
 358                                 if (signal_usr2 || signal_term)
 359                                         break; // Other signal type
 360
 361                                 // Send renew as T1 expired
 362                                 size_t ia_pd_len, ia_na_len;
 363                                 odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 364                                 odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 365
 366                                 // If we have any IAs, send renew, otherwise request
 367                                 if (ia_pd_len == 0 && ia_na_len == 0)
 368                                         res = dhcpv6_request(DHCPV6_MSG_REQUEST);
 369                                 else
 370                                         res = dhcpv6_request(DHCPV6_MSG_RENEW);
 371
 372                                 odhcp6c_signal_process();
 373                                 if (res > 0) { // Renew was succesfull
 374                                         // Publish updates
 375                                         script_call("updated");
 376                                         continue; // Renew was successful
 377                                 }
 378
 379                                 odhcp6c_clear_state(STATE_SERVER_ID); // Remove binding
 380
 381                                 // If we have IAs, try rebind otherwise restart
 382                                 res = dhcpv6_request(DHCPV6_MSG_REBIND);
 383                                 odhcp6c_signal_process();
 384
 385                                 if (res > 0)
 386                                         script_call("rebound");
 387                                 else {
 388 #ifdef EXT_BFD_PING
 389                                         bfd_stop();
 390 #endif
 391                                         break;
 392                                 }
 393                         }
 394                         break;
 395
 396                 default:
 397                         break;
 398                 }
 399
 400                 size_t ia_pd_len, ia_na_len, server_id_len;
 401                 odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 402                 odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 403                 odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 404
 405                 // Add all prefixes to lost prefixes
 406                 bound = false;
 407                 script_call("unbound");
 408
 409                 if (server_id_len > 0 && (ia_pd_len > 0 || ia_na_len > 0) && release)
 410                         dhcpv6_request(DHCPV6_MSG_RELEASE);
 411
 412                 odhcp6c_clear_state(STATE_IA_NA);
 413                 odhcp6c_clear_state(STATE_IA_PD);
 414         }
 415
 416         script_call("stopped");
 417         return 0;
 418 }
 419
 420
 421 static int usage(void)
 422 {
 423         const char buf[] =
 424         "Usage: odhcp6c [options] <interface>\n"
 425         "\nFeature options:\n"
 426         "       -S <time>       Wait at least <time> sec for a DHCP-server (0)\n"
 427         "       -N <mode>       Mode for requesting addresses [try|force|none]\n"
 428         "       -P <length>     Request IPv6-Prefix (0 = auto)\n"
 429         "       -F              Force IPv6-Prefix\n"
 430         "       -V <hex-string> Set vendor-class option. string length must be a multiple of 2\n"
 431 #ifdef EXT_BFD_PING
 432         "       -B <interval>   Enable BFD ping check\n"
 433 #endif
 434         "       -c <clientid>   Override client-ID (base-16 encoded)\n"
 435         "       -i <iface-id>   Use a custom interface identifier for RA handling\n"
 436         "       -r <options>    Options to be requested (comma-separated)\n"
 437         "       -R              Do not request any options except those specified with -r\n"
 438         "       -s <script>     Status update script (/usr/sbin/odhcp6c-update)\n"
 439         "       -a              Don't send Accept Reconfigure option\n"
 440         "       -f              Don't send Client FQDN option\n"
 441         "       -k              Don't send a RELEASE when stopping\n"
 442         "       -t <seconds>    Maximum timeout for DHCPv6-SOLICIT (120)\n"
 443         "\nInvocation options:\n"
 444         "       -p <pidfile>    Set pidfile (/var/run/odhcp6c.pid)\n"
 445         "       -d              Daemonize\n"
 446         "       -e              Write logmessages to stderr\n"
 447         //"     -v              Increase logging verbosity\n"
 448         "       -h              Show this help\n\n";
 449         write(STDERR_FILENO, buf, sizeof(buf));
 450         return 1;
 451 }
 452
 453
 454 // Don't want to pull-in librt and libpthread just for a monotonic clock...
 455 uint64_t odhcp6c_get_milli_time(void)
 456 {
 457         struct timespec t = {0, 0};
 458         syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &t);
 459         return t.tv_sec * 1000 + t.tv_nsec / 1000000;
 460 }
 461
 462
 463 static uint8_t* odhcp6c_resize_state(enum odhcp6c_state state, ssize_t len)
 464 {
 465         if (len == 0)
 466                 return state_data[state] + state_len[state];
 467         else if (state_len[state] + len > 1024)
 468                 return NULL;
 469
 470         uint8_t *n = realloc(state_data[state], state_len[state] + len);
 471         if (n || state_len[state] + len == 0) {
 472                 state_data[state] = n;
 473                 n += state_len[state];
 474                 state_len[state] += len;
 475         }
 476         return n;
 477 }
 478
 479
 480 bool odhcp6c_signal_process(void)
 481 {
 482         while (signal_io) {
 483                 signal_io = false;
 484
 485                 bool ra_updated = ra_process();
 486
 487                 if (ra_link_up())
 488                         signal_usr2 = true;
 489
 490                 if (ra_updated && (bound || allow_slaac_only == 0))
 491                         script_call("ra-updated"); // Immediate process urgent events
 492                 else if (ra_updated && !bound && allow_slaac_only > 0)
 493                         script_delay_call("ra-updated", allow_slaac_only);
 494
 495 #ifdef EXT_BFD_PING
 496                 bfd_receive();
 497 #endif
 498         }
 499
 500         return signal_usr1 || signal_usr2 || signal_term;
 501 }
 502
 503
 504 void odhcp6c_clear_state(enum odhcp6c_state state)
 505 {
 506         state_len[state] = 0;
 507 }
 508
 509
 510 void odhcp6c_add_state(enum odhcp6c_state state, const void *data, size_t len)
 511 {
 512         uint8_t *n = odhcp6c_resize_state(state, len);
 513         if (n)
 514                 memcpy(n, data, len);
 515 }
 516
 517 void odhcp6c_insert_state(enum odhcp6c_state state, size_t offset, const void *data, size_t len)
 518 {
 519         ssize_t len_after = state_len[state] - offset;
 520         if (len_after < 0)
 521                 return;
 522
 523         uint8_t *n = odhcp6c_resize_state(state, len);
 524         if (n) {
 525                 uint8_t *sdata = state_data[state];
 526
 527                 memmove(sdata + offset + len, sdata + offset, len_after);
 528                 memcpy(sdata + offset, data, len);
 529         }
 530 }
 531
 532 size_t odhcp6c_remove_state(enum odhcp6c_state state, size_t offset, size_t len)
 533 {
 534         uint8_t *data = state_data[state];
 535         ssize_t len_after = state_len[state] - (offset + len);
 536         if (len_after < 0)
 537                 return state_len[state];
 538
 539         memmove(data + offset, data + offset + len, len_after);
 540         return state_len[state] -= len;
 541 }
 542
 543
 544 void* odhcp6c_move_state(enum odhcp6c_state state, size_t *len)
 545 {
 546         *len = state_len[state];
 547         void *data = state_data[state];
 548
 549         state_len[state] = 0;
 550         state_data[state] = NULL;
 551
 552         return data;
 553 }
 554
 555
 556 void* odhcp6c_get_state(enum odhcp6c_state state, size_t *len)
 557 {
 558         *len = state_len[state];
 559         return state_data[state];
 560 }
 561
 562
 563 struct odhcp6c_entry* odhcp6c_find_entry(enum odhcp6c_state state, const struct odhcp6c_entry *new)
 564 {
 565         size_t len, cmplen = offsetof(struct odhcp6c_entry, target) + new->length / 8;
 566         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 567         struct odhcp6c_entry *x = NULL;
 568
 569         for (struct odhcp6c_entry *c = start; !x && c < &start[len/sizeof(*c)]; ++c)
 570                 if (!memcmp(c, new, cmplen))
 571                         return c;
 572
 573         return NULL;
 574 }
 575
 576
 577 bool odhcp6c_update_entry_safe(enum odhcp6c_state state, struct odhcp6c_entry *new, uint32_t safe)
 578 {
 579         size_t len;
 580         struct odhcp6c_entry *x = odhcp6c_find_entry(state, new);
 581         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 582
 583         if (x && x->valid > new->valid && new->valid < safe)
 584                 new->valid = safe;
 585
 586         if (new->valid > 0) {
 587                 if (x) {
 588                         if (new->valid >= x->valid && new->valid - x->valid < 60 &&
 589                                         new->preferred >= x->preferred &&
 590                                         new->preferred - x->preferred < 60 &&
 591                                         x->class == new->class)
 592                                 return false;
 593                         x->valid = new->valid;
 594                         x->preferred = new->preferred;
 595                         x->t1 = new->t1;
 596                         x->t2 = new->t2;
 597                         x->class = new->class;
 598                         x->iaid = new->iaid;
 599                 } else {
 600                         odhcp6c_add_state(state, new, sizeof(*new));
 601                 }
 602         } else if (x) {
 603                 odhcp6c_remove_state(state, (x - start) * sizeof(*x), sizeof(*x));
 604         }
 605         return true;
 606 }
 607
 608
 609 bool odhcp6c_update_entry(enum odhcp6c_state state, struct odhcp6c_entry *new)
 610 {
 611         return odhcp6c_update_entry_safe(state, new, 0);
 612 }
 613
 614
 615 static void odhcp6c_expire_list(enum odhcp6c_state state, uint32_t elapsed)
 616 {
 617         size_t len;
 618         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 619         for (struct odhcp6c_entry *c = start; c < &start[len / sizeof(*c)]; ++c) {
 620                 if (c->t1 < elapsed)
 621                         c->t1 = 0;
 622                 else if (c->t1 != UINT32_MAX)
 623                         c->t1 -= elapsed;
 624
 625                 if (c->t2 < elapsed)
 626                         c->t2 = 0;
 627                 else if (c->t2 != UINT32_MAX)
 628                         c->t2 -= elapsed;
 629
 630                 if (c->preferred < elapsed)
 631                         c->preferred = 0;
 632                 else if (c->preferred != UINT32_MAX)
 633                         c->preferred -= elapsed;
 634
 635                 if (c->valid < elapsed)
 636                         c->valid = 0;
 637                 else if (c->valid != UINT32_MAX)
 638                         c->valid -= elapsed;
 639
 640                 if (!c->valid)
 641                         odhcp6c_remove_state(state, (c - start) * sizeof(*c), sizeof(*c));
 642         }
 643 }
 644
 645
 646 void odhcp6c_expire(void)
 647 {
 648         time_t now = odhcp6c_get_milli_time() / 1000;
 649         uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 650         last_update = now;
 651
 652         odhcp6c_expire_list(STATE_RA_PREFIX, elapsed);
 653         odhcp6c_expire_list(STATE_RA_ROUTE, elapsed);
 654         odhcp6c_expire_list(STATE_RA_DNS, elapsed);
 655         odhcp6c_expire_list(STATE_IA_NA, elapsed);
 656         odhcp6c_expire_list(STATE_IA_PD, elapsed);
 657 }
 658
 659
 660 uint32_t odhcp6c_elapsed(void)
 661 {
 662         return odhcp6c_get_milli_time() / 1000 - last_update;
 663 }
 664
 665
 666 void odhcp6c_random(void *buf, size_t len)
 667 {
 668         read(urandom_fd, buf, len);
 669 }
 670
 671 bool odhcp6c_is_bound(void)
 672 {
 673         return bound;
 674 }
 675
 676 static void sighandler(int signal)
 677 {
 678         if (signal == SIGCHLD)
 679                 while (waitpid(-1, NULL, WNOHANG) > 0);
 680         else if (signal == SIGUSR1)
 681                 signal_usr1 = true;
 682         else if (signal == SIGUSR2)
 683                 signal_usr2 = true;
 684         else if (signal == SIGIO)
 685                 signal_io = true;
 686         else
 687                 signal_term = true;
 688 }