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
  31 #include "odhcp6c.h"
  32 #include "ra.h"
  33
  34
  35 static void sighandler(int signal);
  36 static int usage(void);
  37
  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
  46
  47 int main(_unused int argc, char* const argv[])
  48 {
  49         // Allocate ressources
  50         const char *pidfile = NULL;
  51         const char *script = "/usr/sbin/odhcp6c-update";
  52         ssize_t l;
  53         uint8_t buf[134];
  54         char *optpos;
  55         uint16_t opttype;
  56         enum odhcp6c_ia_mode ia_na_mode = IA_MODE_TRY;
  57
  58         bool help = false, daemonize = false;
  59         int logopt = LOG_PID;
  60         int c, request_pd = 0;
  61         while ((c = getopt(argc, argv, "S::N:P:c:r:s:khedp:")) != -1) {
  62                 switch (c) {
  63                 case 'S':
  64                         allow_slaac_only = (optarg) ? atoi(optarg) : -1;
  65                         break;
  66
  67                 case 'N':
  68                         if (!strcmp(optarg, "force"))
  69                                 ia_na_mode = IA_MODE_FORCE;
  70                         else if (!strcmp(optarg, "none"))
  71                                 ia_na_mode = IA_MODE_NONE;
  72                         else if (!strcmp(optarg, "try"))
  73                                 ia_na_mode = IA_MODE_TRY;
  74                         else
  75                                 help = true;
  76                         break;
  77
  78                 case 'P':
  79                         if (allow_slaac_only >= 0 && allow_slaac_only < 10)
  80                                 allow_slaac_only = 10;
  81
  82                         request_pd = strtoul(optarg, NULL, 10);
  83                         if (request_pd == 0)
  84                                 request_pd = -1;
  85                         break;
  86
  87                 case 'c':
  88                         l = script_unhexlify(&buf[4], sizeof(buf) - 4, optarg);
  89                         if (l > 0) {
  90                                 buf[0] = 0;
  91                                 buf[1] = DHCPV6_OPT_CLIENTID;
  92                                 buf[2] = 0;
  93                                 buf[3] = l;
  94                                 odhcp6c_add_state(STATE_CLIENT_ID, buf, l + 4);
  95                         } else {
  96                                 help = true;
  97                         }
  98                         break;
  99
 100                 case 'r':
 101                         optpos = optarg;
 102                         while (optpos[0]) {
 103                                 opttype = htons(strtoul(optarg, &optpos, 10));
 104                                 if (optpos == optarg)
 105                                         break;
 106                                 else if (optpos[0])
 107                                         optarg = &optpos[1];
 108                                 odhcp6c_add_state(STATE_ORO, &opttype, 2);
 109                         }
 110                         break;
 111
 112                 case 's':
 113                         script = optarg;
 114                         break;
 115
 116                 case 'k':
 117                         release = false;
 118                         break;
 119
 120                 case 'e':
 121                         logopt |= LOG_PERROR;
 122                         break;
 123
 124                 case 'd':
 125                         daemonize = true;
 126                         break;
 127
 128                 case 'p':
 129                         pidfile = optarg;
 130                         break;
 131
 132                 default:
 133                         help = true;
 134                         break;
 135                 }
 136         }
 137
 138         openlog("odhcp6c", logopt, LOG_DAEMON);
 139         const char *ifname = argv[optind];
 140
 141         if (help || !ifname)
 142                 return usage();
 143
 144         signal(SIGIO, sighandler);
 145         signal(SIGHUP, sighandler);
 146         signal(SIGINT, sighandler);
 147         signal(SIGCHLD, sighandler);
 148         signal(SIGTERM, sighandler);
 149         signal(SIGUSR1, sighandler);
 150         signal(SIGUSR2, sighandler);
 151
 152         if ((urandom_fd = open("/dev/urandom", O_CLOEXEC | O_RDONLY)) < 0 ||
 153                         init_dhcpv6(ifname, request_pd) || ra_init(ifname) ||
 154                         script_init(script, ifname)) {
 155                 syslog(LOG_ERR, "failed to initialize: %s", strerror(errno));
 156                 return 3;
 157         }
 158
 159         if (daemonize) {
 160                 openlog("odhcp6c", LOG_PID, LOG_DAEMON); // Disable LOG_PERROR
 161                 if (daemon(0, 0)) {
 162                         syslog(LOG_ERR, "Failed to daemonize: %s",
 163                                         strerror(errno));
 164                         return 4;
 165                 }
 166
 167                 char pidbuf[128];
 168                 if (!pidfile) {
 169                         snprintf(pidbuf, sizeof(pidbuf),
 170                                         "/var/run/odhcp6c.%s.pid", ifname);
 171                         pidfile = pidbuf;
 172                 }
 173
 174                 int fd = open(pidfile, O_WRONLY | O_CREAT);
 175                 if (fd >= 0) {
 176                         char buf[8];
 177                         int len = snprintf(buf, sizeof(buf), "%i\n", getpid());
 178                         write(fd, buf, len);
 179                         close(fd);
 180                 }
 181         }
 182
 183         script_call("started");
 184
 185         while (do_signal != SIGTERM) { // Main logic
 186                 odhcp6c_clear_state(STATE_SERVER_ID);
 187                 odhcp6c_clear_state(STATE_SERVER_CAND);
 188                 odhcp6c_clear_state(STATE_IA_PD);
 189                 odhcp6c_clear_state(STATE_SNTP_IP);
 190                 odhcp6c_clear_state(STATE_SNTP_FQDN);
 191                 odhcp6c_clear_state(STATE_SIP_IP);
 192                 odhcp6c_clear_state(STATE_SIP_FQDN);
 193                 dhcpv6_set_ia_na_mode(ia_na_mode);
 194                 bound = false;
 195
 196                 syslog(LOG_NOTICE, "(re)starting transaction on %s", ifname);
 197
 198                 do_signal = 0;
 199                 int res = dhcpv6_request(DHCPV6_MSG_SOLICIT);
 200                 odhcp6c_signal_process();
 201
 202                 if (res < 0) {
 203                         continue; // Might happen if we got a signal
 204                 } else if (res == DHCPV6_STATELESS) { // Stateless mode
 205                         while (do_signal == 0 || do_signal == SIGUSR1) {
 206                                 do_signal = 0;
 207
 208                                 res = dhcpv6_request(DHCPV6_MSG_INFO_REQ);
 209                                 odhcp6c_signal_process();
 210                                 if (do_signal == SIGUSR1)
 211                                         continue;
 212                                 else if (res < 0)
 213                                         break;
 214                                 else if (res > 0)
 215                                         script_call("informed");
 216
 217                                 bound = true;
 218                                 syslog(LOG_NOTICE, "entering stateless-mode on %s", ifname);
 219
 220                                 if (dhcpv6_poll_reconfigure() > 0)
 221                                         script_call("informed");
 222                         }
 223
 224                         continue;
 225                 }
 226
 227                 // Stateful mode
 228                 if (dhcpv6_request(DHCPV6_MSG_REQUEST) < 0)
 229                         continue;
 230
 231                 odhcp6c_signal_process();
 232                 script_call("bound");
 233                 bound = true;
 234                 syslog(LOG_NOTICE, "entering stateful-mode on %s", ifname);
 235
 236                 while (do_signal == 0 || do_signal == SIGUSR1) {
 237                         // Renew Cycle
 238                         // Wait for T1 to expire or until we get a reconfigure
 239                         int res = dhcpv6_poll_reconfigure();
 240                         odhcp6c_signal_process();
 241                         if (res >= 0) {
 242                                 if (res > 0)
 243                                         script_call("updated");
 244
 245                                 continue;
 246                         }
 247
 248                         // Handle signal, if necessary
 249                         if (do_signal == SIGUSR1)
 250                                 do_signal = 0; // Acknowledged
 251                         else if (do_signal > 0)
 252                                 break; // Other signal type
 253
 254                         size_t ia_pd_len, ia_na_len, ia_pd_new, ia_na_new;
 255                         odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 256                         odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 257
 258                         // If we have any IAs, send renew, otherwise request
 259                         int r;
 260                         if (ia_pd_len == 0 && ia_na_len == 0)
 261                                 r = dhcpv6_request(DHCPV6_MSG_REQUEST);
 262                         else
 263                                 r = dhcpv6_request(DHCPV6_MSG_RENEW);
 264                         odhcp6c_signal_process();
 265                         if (r > 0) // Publish updates
 266                                 script_call("updated");
 267                         if (r >= 0)
 268                                 continue; // Renew was successful
 269
 270                         odhcp6c_clear_state(STATE_SERVER_ID); // Remove binding
 271
 272                         // If we have IAs, try rebind otherwise restart
 273                         res = dhcpv6_request(DHCPV6_MSG_REBIND);
 274                         odhcp6c_signal_process();
 275
 276                         odhcp6c_get_state(STATE_IA_PD, &ia_pd_new);
 277                         odhcp6c_get_state(STATE_IA_NA, &ia_na_new);
 278                         if (res < 0 || (ia_pd_new == 0 && ia_pd_len) ||
 279                                         (ia_na_new == 0 && ia_na_len))
 280                                 break; // We lost all our IAs, restart
 281                         else if (res > 0)
 282                                 script_call("rebound");
 283                 }
 284
 285
 286                 size_t ia_pd_len, ia_na_len, server_id_len;
 287                 odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 288                 odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 289                 odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 290
 291                 // Add all prefixes to lost prefixes
 292                 bound = false;
 293                 script_call("unbound");
 294
 295                 if (server_id_len > 0 && (ia_pd_len > 0 || ia_na_len > 0) && release)
 296                         dhcpv6_request(DHCPV6_MSG_RELEASE);
 297
 298                 odhcp6c_clear_state(STATE_IA_NA);
 299                 odhcp6c_clear_state(STATE_IA_PD);
 300         }
 301
 302         script_call("stopped");
 303         return 0;
 304 }
 305
 306
 307 static int usage(void)
 308 {
 309         const char buf[] =
 310         "Usage: odhcp6c [options] <interface>\n"
 311         "\nFeature options:\n"
 312         "       -S <time>       Wait at least <time> sec for a DHCP-server (0)\n"
 313         "       -N <mode>       Mode for requesting addresses [try|force|none]\n"
 314         "       -P <length>     Request IPv6-Prefix (0 = auto)\n"
 315         "       -c <clientid>   Override client-ID (base-16 encoded)\n"
 316         "       -r <options>    Options to be requested (comma-separated)\n"
 317         "       -s <script>     Status update script (/usr/sbin/odhcp6c-update)\n"
 318         "       -k              Don't send a RELEASE when stopping\n"
 319         "\nInvocation options:\n"
 320         "       -p <pidfile>    Set pidfile (/var/run/6relayd.pid)\n"
 321         "       -d              Daemonize\n"
 322         "       -e              Write logmessages to stderr\n"
 323         //"     -v              Increase logging verbosity\n"
 324         "       -h              Show this help\n\n";
 325         write(STDERR_FILENO, buf, sizeof(buf));
 326         return 1;
 327 }
 328
 329
 330 // Don't want to pull-in librt and libpthread just for a monotonic clock...
 331 uint64_t odhcp6c_get_milli_time(void)
 332 {
 333         struct timespec t = {0, 0};
 334         syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &t);
 335         return t.tv_sec * 1000 + t.tv_nsec / 1000000;
 336 }
 337
 338
 339 static uint8_t* odhcp6c_resize_state(enum odhcp6c_state state, ssize_t len)
 340 {
 341         if (len == 0)
 342                 return state_data[state] + state_len[state];
 343         else if (state_len[state] + len > 1024)
 344                 return NULL;
 345
 346         uint8_t *n = realloc(state_data[state], state_len[state] + len);
 347         if (n || state_len[state] + len == 0) {
 348                 state_data[state] = n;
 349                 n += state_len[state];
 350                 state_len[state] += len;
 351         }
 352         return n;
 353 }
 354
 355
 356 bool odhcp6c_signal_process(void)
 357 {
 358         if (do_signal == SIGIO) {
 359                 do_signal = 0;
 360                 bool ra_updated = ra_process();
 361
 362                 if (ra_rtnl_process() || (ra_updated && (bound || allow_slaac_only == 0)))
 363                         script_call("ra-updated"); // Immediate process urgent events
 364                 else if (ra_updated && !bound && allow_slaac_only > 0)
 365                         script_delay_call("ra-updated", allow_slaac_only);
 366         }
 367
 368         return do_signal != 0;
 369 }
 370
 371
 372 void odhcp6c_clear_state(enum odhcp6c_state state)
 373 {
 374         state_len[state] = 0;
 375 }
 376
 377
 378 void odhcp6c_add_state(enum odhcp6c_state state, const void *data, size_t len)
 379 {
 380         uint8_t *n = odhcp6c_resize_state(state, len);
 381         if (n)
 382                 memcpy(n, data, len);
 383 }
 384
 385
 386 size_t odhcp6c_remove_state(enum odhcp6c_state state, size_t offset, size_t len)
 387 {
 388         uint8_t *data = state_data[state];
 389         ssize_t len_after = state_len[state] - (offset + len);
 390         if (len_after < 0)
 391                 return state_len[state];
 392
 393         memmove(data + offset, data + offset + len, len_after);
 394         return state_len[state] -= len;
 395 }
 396
 397
 398 void* odhcp6c_get_state(enum odhcp6c_state state, size_t *len)
 399 {
 400         *len = state_len[state];
 401         return state_data[state];
 402 }
 403
 404
 405 struct odhcp6c_entry* odhcp6c_find_entry(enum odhcp6c_state state, const struct odhcp6c_entry *new)
 406 {
 407         size_t len, cmplen = offsetof(struct odhcp6c_entry, target) + new->length / 8;
 408         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 409         struct odhcp6c_entry *x = NULL;
 410
 411         for (struct odhcp6c_entry *c = start; !x && c < &start[len/sizeof(*c)]; ++c)
 412                 if (!memcmp(c, new, cmplen))
 413                         return c;
 414
 415         return NULL;
 416 }
 417
 418
 419 void odhcp6c_update_entry_safe(enum odhcp6c_state state, struct odhcp6c_entry *new, uint32_t safe)
 420 {
 421         size_t len;
 422         struct odhcp6c_entry *x = odhcp6c_find_entry(state, new);
 423         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 424
 425         if (x && x->valid > new->valid && new->valid < safe)
 426                 new->valid = safe;
 427
 428         if (new->valid > 0) {
 429                 if (x) {
 430                         x->valid = new->valid;
 431                         x->preferred = new->preferred;
 432                 } else {
 433                         odhcp6c_add_state(state, new, sizeof(*new));
 434                 }
 435         } else if (x) {
 436                 odhcp6c_remove_state(state, (x - start) * sizeof(*x), sizeof(*x));
 437         }
 438 }
 439
 440
 441 void odhcp6c_update_entry(enum odhcp6c_state state, struct odhcp6c_entry *new)
 442 {
 443         odhcp6c_update_entry_safe(state, new, 0);
 444 }
 445
 446
 447 static void odhcp6c_expire_list(enum odhcp6c_state state, uint32_t elapsed)
 448 {
 449         size_t len;
 450         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 451         for (struct odhcp6c_entry *c = start; c < &start[len / sizeof(*c)]; ++c) {
 452                 if (c->preferred < elapsed)
 453                         c->preferred = 0;
 454                 else if (c->preferred != UINT32_MAX)
 455                         c->preferred -= elapsed;
 456
 457                 if (c->valid < elapsed)
 458                         c->valid = 0;
 459                 else if (c->valid != UINT32_MAX)
 460                         c->valid -= elapsed;
 461
 462                 if (!c->valid)
 463                         odhcp6c_remove_state(state, (c - start) * sizeof(*c), sizeof(*c));
 464         }
 465 }
 466
 467
 468 void odhcp6c_expire(void)
 469 {
 470         static time_t last_update = 0;
 471         time_t now = odhcp6c_get_milli_time() / 1000;
 472
 473         uint32_t elapsed = now - last_update;
 474         last_update = now;
 475
 476         odhcp6c_expire_list(STATE_RA_PREFIX, elapsed);
 477         odhcp6c_expire_list(STATE_RA_ROUTE, elapsed);
 478         odhcp6c_expire_list(STATE_RA_DNS, elapsed);
 479         odhcp6c_expire_list(STATE_IA_NA, elapsed);
 480         odhcp6c_expire_list(STATE_IA_PD, elapsed);
 481 }
 482
 483
 484 void odhcp6c_random(void *buf, size_t len)
 485 {
 486         read(urandom_fd, buf, len);
 487 }
 488
 489
 490 static void sighandler(int signal)
 491 {
 492         if (signal == SIGCHLD)
 493                 while (waitpid(-1, NULL, WNOHANG) > 0);
 494         else if (signal == SIGUSR1)
 495                 do_signal = SIGUSR1;
 496         else if (signal == SIGUSR2)
 497                 do_signal = SIGUSR2;
 498         else if (signal == SIGIO)
 499                 do_signal = SIGIO;
 500         else
 501                 do_signal = SIGTERM;
 502 }