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 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
  59         bool help = false, daemonize = false;
  60         int logopt = LOG_PID;
  61         int c, request_pd = 0;
  62         while ((c = getopt(argc, argv, "S::N:P:c:r:s:khedp:")) != -1) {
  63                 switch (c) {
  64                 case 'S':
  65                         allow_slaac_only = (optarg) ? atoi(optarg) : -1;
  66                         break;
  67
  68                 case 'N':
  69                         if (!strcmp(optarg, "force"))
  70                                 ia_na_mode = IA_MODE_FORCE;
  71                         else if (!strcmp(optarg, "none"))
  72                                 ia_na_mode = IA_MODE_NONE;
  73                         else if (!strcmp(optarg, "try"))
  74                                 ia_na_mode = IA_MODE_TRY;
  75                         else
  76                                 help = true;
  77                         break;
  78
  79                 case 'P':
  80                         if (allow_slaac_only >= 0 && allow_slaac_only < 10)
  81                                 allow_slaac_only = 10;
  82
  83                         request_pd = strtoul(optarg, NULL, 10);
  84                         if (request_pd == 0)
  85                                 request_pd = -1;
  86                         break;
  87
  88                 case 'c':
  89                         l = script_unhexlify(&buf[4], sizeof(buf) - 4, optarg);
  90                         if (l > 0) {
  91                                 buf[0] = 0;
  92                                 buf[1] = DHCPV6_OPT_CLIENTID;
  93                                 buf[2] = 0;
  94                                 buf[3] = l;
  95                                 odhcp6c_add_state(STATE_CLIENT_ID, buf, l + 4);
  96                         } else {
  97                                 help = true;
  98                         }
  99                         break;
 100
 101                 case 'r':
 102                         optpos = optarg;
 103                         while (optpos[0]) {
 104                                 opttype = htons(strtoul(optarg, &optpos, 10));
 105                                 if (optpos == optarg)
 106                                         break;
 107                                 else if (optpos[0])
 108                                         optarg = &optpos[1];
 109                                 odhcp6c_add_state(STATE_ORO, &opttype, 2);
 110                         }
 111                         break;
 112
 113                 case 's':
 114                         script = optarg;
 115                         break;
 116
 117                 case 'k':
 118                         release = false;
 119                         break;
 120
 121                 case 'e':
 122                         logopt |= LOG_PERROR;
 123                         break;
 124
 125                 case 'd':
 126                         daemonize = true;
 127                         break;
 128
 129                 case 'p':
 130                         pidfile = optarg;
 131                         break;
 132
 133                 default:
 134                         help = true;
 135                         break;
 136                 }
 137         }
 138
 139         openlog("odhcp6c", logopt, LOG_DAEMON);
 140         const char *ifname = argv[optind];
 141
 142         if (help || !ifname)
 143                 return usage();
 144
 145         signal(SIGIO, sighandler);
 146         signal(SIGHUP, sighandler);
 147         signal(SIGINT, sighandler);
 148         signal(SIGCHLD, sighandler);
 149         signal(SIGTERM, sighandler);
 150         signal(SIGUSR1, sighandler);
 151         signal(SIGUSR2, sighandler);
 152
 153         if ((urandom_fd = open("/dev/urandom", O_CLOEXEC | O_RDONLY)) < 0 ||
 154                         init_dhcpv6(ifname, request_pd) || ra_init(ifname) ||
 155                         script_init(script, ifname)) {
 156                 syslog(LOG_ERR, "failed to initialize: %s", strerror(errno));
 157                 return 3;
 158         }
 159
 160         if (daemonize) {
 161                 openlog("odhcp6c", LOG_PID, LOG_DAEMON); // Disable LOG_PERROR
 162                 if (daemon(0, 0)) {
 163                         syslog(LOG_ERR, "Failed to daemonize: %s",
 164                                         strerror(errno));
 165                         return 4;
 166                 }
 167
 168                 char pidbuf[128];
 169                 if (!pidfile) {
 170                         snprintf(pidbuf, sizeof(pidbuf),
 171                                         "/var/run/odhcp6c.%s.pid", ifname);
 172                         pidfile = pidbuf;
 173                 }
 174
 175                 int fd = open(pidfile, O_WRONLY | O_CREAT);
 176                 if (fd >= 0) {
 177                         char buf[8];
 178                         int len = snprintf(buf, sizeof(buf), "%i\n", getpid());
 179                         write(fd, buf, len);
 180                         close(fd);
 181                 }
 182         }
 183
 184         script_call("started");
 185
 186         while (do_signal != SIGTERM) { // Main logic
 187                 odhcp6c_clear_state(STATE_SERVER_ID);
 188                 odhcp6c_clear_state(STATE_SERVER_CAND);
 189                 odhcp6c_clear_state(STATE_IA_PD);
 190                 odhcp6c_clear_state(STATE_SNTP_IP);
 191                 odhcp6c_clear_state(STATE_SNTP_FQDN);
 192                 odhcp6c_clear_state(STATE_SIP_IP);
 193                 odhcp6c_clear_state(STATE_SIP_FQDN);
 194                 dhcpv6_set_ia_na_mode(ia_na_mode);
 195                 bound = false;
 196
 197                 syslog(LOG_NOTICE, "(re)starting transaction on %s", ifname);
 198
 199                 do_signal = 0;
 200                 int res = dhcpv6_request(DHCPV6_MSG_SOLICIT);
 201                 odhcp6c_signal_process();
 202
 203                 if (res < 0) {
 204                         continue; // Might happen if we got a signal
 205                 } else if (res == DHCPV6_STATELESS) { // Stateless mode
 206                         while (do_signal == 0 || do_signal == SIGUSR1) {
 207                                 do_signal = 0;
 208
 209                                 res = dhcpv6_request(DHCPV6_MSG_INFO_REQ);
 210                                 odhcp6c_signal_process();
 211                                 if (do_signal == SIGUSR1)
 212                                         continue;
 213                                 else if (res < 0)
 214                                         break;
 215                                 else if (res > 0)
 216                                         script_call("informed");
 217
 218                                 bound = true;
 219                                 syslog(LOG_NOTICE, "entering stateless-mode on %s", ifname);
 220
 221                                 if (dhcpv6_poll_reconfigure() > 0)
 222                                         script_call("informed");
 223                         }
 224
 225                         continue;
 226                 }
 227
 228                 // Stateful mode
 229                 if (dhcpv6_request(DHCPV6_MSG_REQUEST) < 0)
 230                         continue;
 231
 232                 odhcp6c_signal_process();
 233                 script_call("bound");
 234                 bound = true;
 235                 syslog(LOG_NOTICE, "entering stateful-mode on %s", ifname);
 236
 237                 while (do_signal == 0 || do_signal == SIGUSR1) {
 238                         // Renew Cycle
 239                         // Wait for T1 to expire or until we get a reconfigure
 240                         int res = dhcpv6_poll_reconfigure();
 241                         odhcp6c_signal_process();
 242                         if (res >= 0) {
 243                                 if (res > 0)
 244                                         script_call("updated");
 245
 246                                 continue;
 247                         }
 248
 249                         // Handle signal, if necessary
 250                         if (do_signal == SIGUSR1)
 251                                 do_signal = 0; // Acknowledged
 252                         else if (do_signal > 0)
 253                                 break; // Other signal type
 254
 255                         size_t ia_pd_len, ia_na_len, ia_pd_new, ia_na_new;
 256                         odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 257                         odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 258
 259                         // If we have any IAs, send renew, otherwise request
 260                         int r;
 261                         if (ia_pd_len == 0 && ia_na_len == 0)
 262                                 r = dhcpv6_request(DHCPV6_MSG_REQUEST);
 263                         else
 264                                 r = dhcpv6_request(DHCPV6_MSG_RENEW);
 265                         odhcp6c_signal_process();
 266                         if (r > 0) // Publish updates
 267                                 script_call("updated");
 268                         if (r >= 0)
 269                                 continue; // Renew was successful
 270
 271                         odhcp6c_clear_state(STATE_SERVER_ID); // Remove binding
 272
 273                         // If we have IAs, try rebind otherwise restart
 274                         res = dhcpv6_request(DHCPV6_MSG_REBIND);
 275                         odhcp6c_signal_process();
 276
 277                         odhcp6c_get_state(STATE_IA_PD, &ia_pd_new);
 278                         odhcp6c_get_state(STATE_IA_NA, &ia_na_new);
 279                         if (res < 0 || (ia_pd_new == 0 && ia_pd_len) ||
 280                                         (ia_na_new == 0 && ia_na_len))
 281                                 break; // We lost all our IAs, restart
 282                         else if (res > 0)
 283                                 script_call("rebound");
 284                 }
 285
 286
 287                 size_t ia_pd_len, ia_na_len, server_id_len;
 288                 odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 289                 odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 290                 odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 291
 292                 // Add all prefixes to lost prefixes
 293                 bound = false;
 294                 script_call("unbound");
 295
 296                 if (server_id_len > 0 && (ia_pd_len > 0 || ia_na_len > 0) && release)
 297                         dhcpv6_request(DHCPV6_MSG_RELEASE);
 298
 299                 odhcp6c_clear_state(STATE_IA_NA);
 300                 odhcp6c_clear_state(STATE_IA_PD);
 301         }
 302
 303         script_call("stopped");
 304         return 0;
 305 }
 306
 307
 308 static int usage(void)
 309 {
 310         const char buf[] =
 311         "Usage: odhcp6c [options] <interface>\n"
 312         "\nFeature options:\n"
 313         "       -S <time>       Wait at least <time> sec for a DHCP-server (0)\n"
 314         "       -N <mode>       Mode for requesting addresses [try|force|none]\n"
 315         "       -P <length>     Request IPv6-Prefix (0 = auto)\n"
 316         "       -c <clientid>   Override client-ID (base-16 encoded)\n"
 317         "       -r <options>    Options to be requested (comma-separated)\n"
 318         "       -s <script>     Status update script (/usr/sbin/odhcp6c-update)\n"
 319         "       -k              Don't send a RELEASE when stopping\n"
 320         "\nInvocation options:\n"
 321         "       -p <pidfile>    Set pidfile (/var/run/6relayd.pid)\n"
 322         "       -d              Daemonize\n"
 323         "       -e              Write logmessages to stderr\n"
 324         //"     -v              Increase logging verbosity\n"
 325         "       -h              Show this help\n\n";
 326         write(STDERR_FILENO, buf, sizeof(buf));
 327         return 1;
 328 }
 329
 330
 331 // Don't want to pull-in librt and libpthread just for a monotonic clock...
 332 uint64_t odhcp6c_get_milli_time(void)
 333 {
 334         struct timespec t = {0, 0};
 335         syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &t);
 336         return t.tv_sec * 1000 + t.tv_nsec / 1000000;
 337 }
 338
 339
 340 static uint8_t* odhcp6c_resize_state(enum odhcp6c_state state, ssize_t len)
 341 {
 342         if (len == 0)
 343                 return state_data[state] + state_len[state];
 344         else if (state_len[state] + len > 1024)
 345                 return NULL;
 346
 347         uint8_t *n = realloc(state_data[state], state_len[state] + len);
 348         if (n || state_len[state] + len == 0) {
 349                 state_data[state] = n;
 350                 n += state_len[state];
 351                 state_len[state] += len;
 352         }
 353         return n;
 354 }
 355
 356
 357 bool odhcp6c_signal_process(void)
 358 {
 359         if (do_signal == SIGIO) {
 360                 do_signal = 0;
 361                 bool ra_rtnled = ra_rtnl_process();
 362                 bool ra_updated = ra_process();
 363
 364                 if (ra_rtnled || (ra_updated && (bound || allow_slaac_only == 0)))
 365                         script_call("ra-updated"); // Immediate process urgent events
 366                 else if (ra_updated && !bound && allow_slaac_only > 0)
 367                         script_delay_call("ra-updated", allow_slaac_only);
 368         }
 369
 370         return do_signal != 0;
 371 }
 372
 373
 374 void odhcp6c_clear_state(enum odhcp6c_state state)
 375 {
 376         state_len[state] = 0;
 377 }
 378
 379
 380 void odhcp6c_add_state(enum odhcp6c_state state, const void *data, size_t len)
 381 {
 382         uint8_t *n = odhcp6c_resize_state(state, len);
 383         if (n)
 384                 memcpy(n, data, len);
 385 }
 386
 387
 388 size_t odhcp6c_remove_state(enum odhcp6c_state state, size_t offset, size_t len)
 389 {
 390         uint8_t *data = state_data[state];
 391         ssize_t len_after = state_len[state] - (offset + len);
 392         if (len_after < 0)
 393                 return state_len[state];
 394
 395         memmove(data + offset, data + offset + len, len_after);
 396         return state_len[state] -= len;
 397 }
 398
 399
 400 void* odhcp6c_get_state(enum odhcp6c_state state, size_t *len)
 401 {
 402         *len = state_len[state];
 403         return state_data[state];
 404 }
 405
 406
 407 struct odhcp6c_entry* odhcp6c_find_entry(enum odhcp6c_state state, const struct odhcp6c_entry *new)
 408 {
 409         size_t len, cmplen = offsetof(struct odhcp6c_entry, target) + new->length / 8;
 410         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 411         struct odhcp6c_entry *x = NULL;
 412
 413         for (struct odhcp6c_entry *c = start; !x && c < &start[len/sizeof(*c)]; ++c)
 414                 if (!memcmp(c, new, cmplen))
 415                         return c;
 416
 417         return NULL;
 418 }
 419
 420
 421 void odhcp6c_update_entry_safe(enum odhcp6c_state state, struct odhcp6c_entry *new, uint32_t safe)
 422 {
 423         size_t len;
 424         struct odhcp6c_entry *x = odhcp6c_find_entry(state, new);
 425         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 426
 427         if (x && x->valid > new->valid && new->valid < safe)
 428                 new->valid = safe;
 429
 430         if (new->valid > 0) {
 431                 if (x) {
 432                         x->valid = new->valid;
 433                         x->preferred = new->preferred;
 434                 } else {
 435                         odhcp6c_add_state(state, new, sizeof(*new));
 436                 }
 437         } else if (x) {
 438                 odhcp6c_remove_state(state, (x - start) * sizeof(*x), sizeof(*x));
 439         }
 440 }
 441
 442
 443 void odhcp6c_update_entry(enum odhcp6c_state state, struct odhcp6c_entry *new)
 444 {
 445         odhcp6c_update_entry_safe(state, new, 0);
 446 }
 447
 448
 449 static void odhcp6c_expire_list(enum odhcp6c_state state, uint32_t elapsed)
 450 {
 451         size_t len;
 452         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 453         for (struct odhcp6c_entry *c = start; c < &start[len / sizeof(*c)]; ++c) {
 454                 if (c->preferred < elapsed)
 455                         c->preferred = 0;
 456                 else if (c->preferred != UINT32_MAX)
 457                         c->preferred -= elapsed;
 458
 459                 if (c->valid < elapsed)
 460                         c->valid = 0;
 461                 else if (c->valid != UINT32_MAX)
 462                         c->valid -= elapsed;
 463
 464                 if (!c->valid)
 465                         odhcp6c_remove_state(state, (c - start) * sizeof(*c), sizeof(*c));
 466         }
 467 }
 468
 469
 470 void odhcp6c_expire(void)
 471 {
 472         time_t now = odhcp6c_get_milli_time() / 1000;
 473         uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 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 uint32_t odhcp6c_elapsed(void)
 485 {
 486         return odhcp6c_get_milli_time() / 1000 - last_update;
 487 }
 488
 489
 490 void odhcp6c_random(void *buf, size_t len)
 491 {
 492         read(urandom_fd, buf, len);
 493 }
 494
 495
 496 static void sighandler(int signal)
 497 {
 498         if (signal == SIGCHLD)
 499                 while (waitpid(-1, NULL, WNOHANG) > 0);
 500         else if (signal == SIGUSR1)
 501                 do_signal = SIGUSR1;
 502         else if (signal == SIGUSR2)
 503                 do_signal = SIGUSR2;
 504         else if (signal == SIGIO)
 505                 do_signal = SIGIO;
 506         else
 507                 do_signal = SIGTERM;
 508 }