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