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