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 = 15;
  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                         request_pd = strtoul(optarg, NULL, 10);
  80                         if (request_pd == 0)
  81                                 request_pd = -1;
  82                         break;
  83
  84                 case 'c':
  85                         l = script_unhexlify(&buf[4], sizeof(buf) - 4, optarg);
  86                         if (l > 0) {
  87                                 buf[0] = 0;
  88                                 buf[1] = DHCPV6_OPT_CLIENTID;
  89                                 buf[2] = 0;
  90                                 buf[3] = l;
  91                                 odhcp6c_add_state(STATE_CLIENT_ID, buf, l + 4);
  92                         } else {
  93                                 help = true;
  94                         }
  95                         break;
  96
  97                 case 'r':
  98                         optpos = optarg;
  99                         while (optpos[0]) {
 100                                 opttype = htons(strtoul(optarg, &optpos, 10));
 101                                 if (optpos == optarg)
 102                                         break;
 103                                 else if (optpos[0])
 104                                         optarg = &optpos[1];
 105                                 odhcp6c_add_state(STATE_ORO, &opttype, 2);
 106                         }
 107                         break;
 108
 109                 case 's':
 110                         script = optarg;
 111                         break;
 112
 113                 case 'k':
 114                         release = false;
 115                         break;
 116
 117                 case 'e':
 118                         logopt |= LOG_PERROR;
 119                         break;
 120
 121                 case 'd':
 122                         daemonize = true;
 123                         break;
 124
 125                 case 'p':
 126                         pidfile = optarg;
 127                         break;
 128
 129                 default:
 130                         help = true;
 131                         break;
 132                 }
 133         }
 134
 135         openlog("odhcp6c", logopt, LOG_DAEMON);
 136         const char *ifname = argv[optind];
 137
 138         if (help || !ifname)
 139                 return usage();
 140
 141         signal(SIGIO, sighandler);
 142         signal(SIGHUP, sighandler);
 143         signal(SIGINT, sighandler);
 144         signal(SIGCHLD, sighandler);
 145         signal(SIGTERM, sighandler);
 146         signal(SIGUSR1, sighandler);
 147         signal(SIGUSR2, sighandler);
 148
 149         if ((urandom_fd = open("/dev/urandom", O_CLOEXEC | O_RDONLY)) < 0 ||
 150                         init_dhcpv6(ifname, request_pd) || ra_init(ifname) ||
 151                         script_init(script, ifname)) {
 152                 syslog(LOG_ERR, "failed to initialize: %s", strerror(errno));
 153                 return 3;
 154         }
 155
 156         if (daemonize) {
 157                 openlog("odhcp6c", LOG_PID, LOG_DAEMON); // Disable LOG_PERROR
 158                 if (daemon(0, 0)) {
 159                         syslog(LOG_ERR, "Failed to daemonize: %s",
 160                                         strerror(errno));
 161                         return 4;
 162                 }
 163
 164                 char pidbuf[128];
 165                 if (!pidfile) {
 166                         snprintf(pidbuf, sizeof(pidbuf),
 167                                         "/var/run/odhcp6c.%s.pid", ifname);
 168                         pidfile = pidbuf;
 169                 }
 170
 171                 int fd = open(pidfile, O_WRONLY | O_CREAT);
 172                 if (fd >= 0) {
 173                         char buf[8];
 174                         int len = snprintf(buf, sizeof(buf), "%i\n", getpid());
 175                         write(fd, buf, len);
 176                         close(fd);
 177                 }
 178         }
 179
 180         script_call("started");
 181
 182         while (do_signal != SIGTERM) { // Main logic
 183                 odhcp6c_clear_state(STATE_SERVER_ID);
 184                 odhcp6c_clear_state(STATE_SERVER_CAND);
 185                 odhcp6c_clear_state(STATE_IA_PD);
 186                 odhcp6c_clear_state(STATE_SNTP_IP);
 187                 odhcp6c_clear_state(STATE_SNTP_FQDN);
 188                 odhcp6c_clear_state(STATE_SIP_IP);
 189                 odhcp6c_clear_state(STATE_SIP_FQDN);
 190                 dhcpv6_set_ia_na_mode(ia_na_mode);
 191                 bound = false;
 192
 193                 syslog(LOG_NOTICE, "(re)starting transaction on %s", ifname);
 194
 195                 do_signal = 0;
 196                 int res = dhcpv6_request(DHCPV6_MSG_SOLICIT);
 197                 odhcp6c_signal_process();
 198
 199                 if (res < 0) {
 200                         continue; // Might happen if we got a signal
 201                 } else if (res == DHCPV6_STATELESS) { // Stateless mode
 202                         while (do_signal == 0 || do_signal == SIGUSR1) {
 203                                 do_signal = 0;
 204
 205                                 res = dhcpv6_request(DHCPV6_MSG_INFO_REQ);
 206                                 odhcp6c_signal_process();
 207                                 if (do_signal == SIGUSR1)
 208                                         continue;
 209                                 else if (res < 0)
 210                                         break;
 211                                 else if (res > 0)
 212                                         script_call("informed");
 213
 214                                 bound = true;
 215                                 syslog(LOG_NOTICE, "entering stateless-mode on %s", ifname);
 216
 217                                 if (dhcpv6_poll_reconfigure() > 0)
 218                                         script_call("informed");
 219                         }
 220
 221                         continue;
 222                 }
 223
 224                 // Stateful mode
 225                 if (dhcpv6_request(DHCPV6_MSG_REQUEST) < 0)
 226                         continue;
 227
 228                 odhcp6c_signal_process();
 229                 script_call("bound");
 230                 bound = true;
 231                 syslog(LOG_NOTICE, "entering stateful-mode on %s", ifname);
 232
 233                 while (do_signal == 0 || do_signal == SIGUSR1) {
 234                         // Renew Cycle
 235                         // Wait for T1 to expire or until we get a reconfigure
 236                         int res = dhcpv6_poll_reconfigure();
 237                         odhcp6c_signal_process();
 238                         if (res >= 0) {
 239                                 if (res > 0)
 240                                         script_call("updated");
 241
 242                                 continue;
 243                         }
 244
 245                         // Handle signal, if necessary
 246                         if (do_signal == SIGUSR1)
 247                                 do_signal = 0; // Acknowledged
 248                         else if (do_signal > 0)
 249                                 break; // Other signal type
 250
 251                         size_t ia_pd_len, ia_na_len, ia_pd_new, ia_na_new;
 252                         odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 253                         odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 254
 255                         // If we have any IAs, send renew, otherwise request
 256                         int r;
 257                         if (ia_pd_len == 0 && ia_na_len == 0)
 258                                 r = dhcpv6_request(DHCPV6_MSG_REQUEST);
 259                         else
 260                                 r = dhcpv6_request(DHCPV6_MSG_RENEW);
 261                         odhcp6c_signal_process();
 262                         if (r > 0) // Publish updates
 263                                 script_call("updated");
 264                         if (r >= 0)
 265                                 continue; // Renew was successful
 266
 267                         odhcp6c_clear_state(STATE_SERVER_ID); // Remove binding
 268
 269                         // If we have IAs, try rebind otherwise restart
 270                         res = dhcpv6_request(DHCPV6_MSG_REBIND);
 271                         odhcp6c_signal_process();
 272
 273                         odhcp6c_get_state(STATE_IA_PD, &ia_pd_new);
 274                         odhcp6c_get_state(STATE_IA_NA, &ia_na_new);
 275                         if (res < 0 || (ia_pd_new == 0 && ia_pd_len) ||
 276                                         (ia_na_new == 0 && ia_na_len))
 277                                 break; // We lost all our IAs, restart
 278                         else if (res > 0)
 279                                 script_call("rebound");
 280                 }
 281
 282
 283                 size_t ia_pd_len, ia_na_len, server_id_len;
 284                 odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 285                 odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 286                 odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 287
 288                 // Add all prefixes to lost prefixes
 289                 bound = false;
 290                 script_call("unbound");
 291
 292                 if (server_id_len > 0 && (ia_pd_len > 0 || ia_na_len > 0) && release)
 293                         dhcpv6_request(DHCPV6_MSG_RELEASE);
 294
 295                 odhcp6c_clear_state(STATE_IA_NA);
 296                 odhcp6c_clear_state(STATE_IA_PD);
 297         }
 298
 299         script_call("stopped");
 300         return 0;
 301 }
 302
 303
 304 static int usage(void)
 305 {
 306         const char buf[] =
 307         "Usage: odhcp6c [options] <interface>\n"
 308         "\nFeature options:\n"
 309         "       -S <time>       Wait at least <time> sec for a DHCP-server (15)\n"
 310         "       -N <mode>       Mode for requesting addresses [try|force|none]\n"
 311         "       -P <length>     Request IPv6-Prefix (0 = auto)\n"
 312         "       -c <clientid>   Override client-ID (base-16 encoded)\n"
 313         "       -r <options>    Options to be requested (comma-separated)\n"
 314         "       -s <script>     Status update script (/usr/sbin/odhcp6c-update)\n"
 315         "       -k              Don't send a RELEASE when stopping\n"
 316         "\nInvocation options:\n"
 317         "       -p <pidfile>    Set pidfile (/var/run/6relayd.pid)\n"
 318         "       -d              Daemonize\n"
 319         "       -e              Write logmessages to stderr\n"
 320         //"     -v              Increase logging verbosity\n"
 321         "       -h              Show this help\n\n";
 322         write(STDERR_FILENO, buf, sizeof(buf));
 323         return 1;
 324 }
 325
 326
 327 // Don't want to pull-in librt and libpthread just for a monotonic clock...
 328 uint64_t odhcp6c_get_milli_time(void)
 329 {
 330         struct timespec t = {0, 0};
 331         syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &t);
 332         return t.tv_sec * 1000 + t.tv_nsec / 1000000;
 333 }
 334
 335
 336 static uint8_t* odhcp6c_resize_state(enum odhcp6c_state state, ssize_t len)
 337 {
 338         if (len == 0)
 339                 return state_data[state] + state_len[state];
 340         else if (state_len[state] + len > 1024)
 341                 return NULL;
 342
 343         uint8_t *n = realloc(state_data[state], state_len[state] + len);
 344         if (n || state_len[state] + len == 0) {
 345                 state_data[state] = n;
 346                 n += state_len[state];
 347                 state_len[state] += len;
 348         }
 349         return n;
 350 }
 351
 352
 353 bool odhcp6c_signal_process(void)
 354 {
 355         if (do_signal == SIGIO) {
 356                 do_signal = 0;
 357                 bool ra_updated = ra_process();
 358
 359                 if (ra_rtnl_process() || (ra_updated && (bound || allow_slaac_only == 0)))
 360                         script_call("ra-updated"); // Immediate process urgent events
 361                 else if (ra_updated && !bound && allow_slaac_only > 0)
 362                         script_delay_call("ra-updated", allow_slaac_only);
 363         }
 364
 365         return do_signal != 0;
 366 }
 367
 368
 369 void odhcp6c_clear_state(enum odhcp6c_state state)
 370 {
 371         state_len[state] = 0;
 372 }
 373
 374
 375 void odhcp6c_add_state(enum odhcp6c_state state, const void *data, size_t len)
 376 {
 377         uint8_t *n = odhcp6c_resize_state(state, len);
 378         if (n)
 379                 memcpy(n, data, len);
 380 }
 381
 382
 383 size_t odhcp6c_remove_state(enum odhcp6c_state state, size_t offset, size_t len)
 384 {
 385         uint8_t *data = state_data[state];
 386         ssize_t len_after = state_len[state] - (offset + len);
 387         if (len_after < 0)
 388                 return state_len[state];
 389
 390         memmove(data + offset, data + offset + len, len_after);
 391         return state_len[state] -= len;
 392 }
 393
 394
 395 void* odhcp6c_get_state(enum odhcp6c_state state, size_t *len)
 396 {
 397         *len = state_len[state];
 398         return state_data[state];
 399 }
 400
 401
 402 struct odhcp6c_entry* odhcp6c_find_entry(enum odhcp6c_state state, const struct odhcp6c_entry *new)
 403 {
 404         size_t len, cmplen = offsetof(struct odhcp6c_entry, target) + new->length / 8;
 405         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 406         struct odhcp6c_entry *x = NULL;
 407
 408         for (struct odhcp6c_entry *c = start; !x && c < &start[len/sizeof(*c)]; ++c)
 409                 if (!memcmp(c, new, cmplen))
 410                         return c;
 411
 412         return NULL;
 413 }
 414
 415
 416 void odhcp6c_update_entry_safe(enum odhcp6c_state state, struct odhcp6c_entry *new, uint32_t safe)
 417 {
 418         size_t len;
 419         struct odhcp6c_entry *x = odhcp6c_find_entry(state, new);
 420         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 421
 422         if (x && x->valid > new->valid && new->valid < safe)
 423                 new->valid = safe;
 424
 425         if (new->valid > 0) {
 426                 if (x) {
 427                         x->valid = new->valid;
 428                         x->preferred = new->preferred;
 429                 } else {
 430                         odhcp6c_add_state(state, new, sizeof(*new));
 431                 }
 432         } else if (x) {
 433                 odhcp6c_remove_state(state, (x - start) * sizeof(*x), sizeof(*x));
 434         }
 435 }
 436
 437
 438 void odhcp6c_update_entry(enum odhcp6c_state state, struct odhcp6c_entry *new)
 439 {
 440         odhcp6c_update_entry_safe(state, new, 0);
 441 }
 442
 443
 444 static void odhcp6c_expire_list(enum odhcp6c_state state, uint32_t elapsed)
 445 {
 446         size_t len;
 447         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 448         for (struct odhcp6c_entry *c = start; c < &start[len / sizeof(*c)]; ++c) {
 449                 if (c->preferred < elapsed)
 450                         c->preferred = 0;
 451                 else if (c->preferred != UINT32_MAX)
 452                         c->preferred -= elapsed;
 453
 454                 if (c->valid < elapsed)
 455                         c->valid = 0;
 456                 else if (c->valid != UINT32_MAX)
 457                         c->valid -= elapsed;
 458
 459                 if (!c->valid)
 460                         odhcp6c_remove_state(state, (c - start) * sizeof(*c), sizeof(*c));
 461         }
 462 }
 463
 464
 465 void odhcp6c_expire(void)
 466 {
 467         static time_t last_update = 0;
 468         time_t now = odhcp6c_get_milli_time() / 1000;
 469
 470         uint32_t elapsed = now - last_update;
 471         last_update = now;
 472
 473         odhcp6c_expire_list(STATE_RA_PREFIX, elapsed);
 474         odhcp6c_expire_list(STATE_RA_ROUTE, elapsed);
 475         odhcp6c_expire_list(STATE_RA_DNS, elapsed);
 476         odhcp6c_expire_list(STATE_IA_NA, elapsed);
 477         odhcp6c_expire_list(STATE_IA_PD, elapsed);
 478 }
 479
 480
 481 void odhcp6c_random(void *buf, size_t len)
 482 {
 483         read(urandom_fd, buf, len);
 484 }
 485
 486
 487 static void sighandler(int signal)
 488 {
 489         if (signal == SIGCHLD)
 490                 while (waitpid(-1, NULL, WNOHANG) > 0);
 491         else if (signal == SIGUSR1)
 492                 do_signal = SIGUSR1;
 493         else if (signal == SIGUSR2)
 494                 do_signal = SIGUSR2;
 495         else if (signal == SIGIO)
 496                 do_signal = SIGIO;
 497         else
 498                 do_signal = SIGTERM;
 499 }