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