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         static struct in6_addr ifid = IN6ADDR_ANY_INIT;
  60
  61         bool help = false, daemonize = false;
  62         int logopt = LOG_PID;
  63         int c, request_pd = 0;
  64         while ((c = getopt(argc, argv, "S::N:P:c:i:r:s:khedp:")) != -1) {
  65                 switch (c) {
  66                 case 'S':
  67                         allow_slaac_only = (optarg) ? atoi(optarg) : -1;
  68                         break;
  69
  70                 case 'N':
  71                         if (!strcmp(optarg, "force"))
  72                                 ia_na_mode = IA_MODE_FORCE;
  73                         else if (!strcmp(optarg, "none"))
  74                                 ia_na_mode = IA_MODE_NONE;
  75                         else if (!strcmp(optarg, "try"))
  76                                 ia_na_mode = IA_MODE_TRY;
  77                         else
  78                                 help = true;
  79                         break;
  80
  81                 case 'P':
  82                         if (allow_slaac_only >= 0 && allow_slaac_only < 10)
  83                                 allow_slaac_only = 10;
  84
  85                         request_pd = strtoul(optarg, NULL, 10);
  86                         if (request_pd == 0)
  87                                 request_pd = -1;
  88                         break;
  89
  90                 case 'c':
  91                         l = script_unhexlify(&buf[4], sizeof(buf) - 4, optarg);
  92                         if (l > 0) {
  93                                 buf[0] = 0;
  94                                 buf[1] = DHCPV6_OPT_CLIENTID;
  95                                 buf[2] = 0;
  96                                 buf[3] = l;
  97                                 odhcp6c_add_state(STATE_CLIENT_ID, buf, l + 4);
  98                         } else {
  99                                 help = true;
 100                         }
 101                         break;
 102
 103                 case 'i':
 104                         if (inet_pton(AF_INET6, optarg, &ifid) != 1)
 105                                 help = true;
 106                         break;
 107
 108                 case 'r':
 109                         optpos = optarg;
 110                         while (optpos[0]) {
 111                                 opttype = htons(strtoul(optarg, &optpos, 10));
 112                                 if (optpos == optarg)
 113                                         break;
 114                                 else if (optpos[0])
 115                                         optarg = &optpos[1];
 116                                 odhcp6c_add_state(STATE_ORO, &opttype, 2);
 117                         }
 118                         break;
 119
 120                 case 's':
 121                         script = optarg;
 122                         break;
 123
 124                 case 'k':
 125                         release = false;
 126                         break;
 127
 128                 case 'e':
 129                         logopt |= LOG_PERROR;
 130                         break;
 131
 132                 case 'd':
 133                         daemonize = true;
 134                         break;
 135
 136                 case 'p':
 137                         pidfile = optarg;
 138                         break;
 139
 140                 default:
 141                         help = true;
 142                         break;
 143                 }
 144         }
 145
 146         openlog("odhcp6c", logopt, LOG_DAEMON);
 147         const char *ifname = argv[optind];
 148
 149         if (help || !ifname)
 150                 return usage();
 151
 152         signal(SIGIO, sighandler);
 153         signal(SIGHUP, sighandler);
 154         signal(SIGINT, sighandler);
 155         signal(SIGCHLD, sighandler);
 156         signal(SIGTERM, sighandler);
 157         signal(SIGUSR1, sighandler);
 158         signal(SIGUSR2, sighandler);
 159
 160         if ((urandom_fd = open("/dev/urandom", O_CLOEXEC | O_RDONLY)) < 0 ||
 161                         init_dhcpv6(ifname, request_pd) || ra_init(ifname, &ifid) ||
 162                         script_init(script, ifname)) {
 163                 syslog(LOG_ERR, "failed to initialize: %s", strerror(errno));
 164                 return 3;
 165         }
 166
 167         if (daemonize) {
 168                 openlog("odhcp6c", LOG_PID, LOG_DAEMON); // Disable LOG_PERROR
 169                 if (daemon(0, 0)) {
 170                         syslog(LOG_ERR, "Failed to daemonize: %s",
 171                                         strerror(errno));
 172                         return 4;
 173                 }
 174
 175                 char pidbuf[128];
 176                 if (!pidfile) {
 177                         snprintf(pidbuf, sizeof(pidbuf),
 178                                         "/var/run/odhcp6c.%s.pid", ifname);
 179                         pidfile = pidbuf;
 180                 }
 181
 182                 int fd = open(pidfile, O_WRONLY | O_CREAT);
 183                 if (fd >= 0) {
 184                         char buf[8];
 185                         int len = snprintf(buf, sizeof(buf), "%i\n", getpid());
 186                         write(fd, buf, len);
 187                         close(fd);
 188                 }
 189         }
 190
 191         script_call("started");
 192
 193         while (do_signal != SIGTERM) { // Main logic
 194                 odhcp6c_clear_state(STATE_SERVER_ID);
 195                 odhcp6c_clear_state(STATE_SERVER_CAND);
 196                 odhcp6c_clear_state(STATE_IA_PD);
 197                 odhcp6c_clear_state(STATE_SNTP_IP);
 198                 odhcp6c_clear_state(STATE_SNTP_FQDN);
 199                 odhcp6c_clear_state(STATE_SIP_IP);
 200                 odhcp6c_clear_state(STATE_SIP_FQDN);
 201                 dhcpv6_set_ia_na_mode(ia_na_mode);
 202                 bound = false;
 203
 204                 syslog(LOG_NOTICE, "(re)starting transaction on %s", ifname);
 205
 206                 do_signal = 0;
 207                 int res = dhcpv6_request(DHCPV6_MSG_SOLICIT);
 208                 odhcp6c_signal_process();
 209
 210                 if (res < 0) {
 211                         continue; // Might happen if we got a signal
 212                 } else if (res == DHCPV6_STATELESS) { // Stateless mode
 213                         while (do_signal == 0 || do_signal == SIGUSR1) {
 214                                 do_signal = 0;
 215
 216                                 res = dhcpv6_request(DHCPV6_MSG_INFO_REQ);
 217                                 odhcp6c_signal_process();
 218                                 if (do_signal == SIGUSR1)
 219                                         continue;
 220                                 else if (res < 0)
 221                                         break;
 222                                 else if (res > 0)
 223                                         script_call("informed");
 224
 225                                 bound = true;
 226                                 syslog(LOG_NOTICE, "entering stateless-mode on %s", ifname);
 227
 228                                 if (dhcpv6_poll_reconfigure() > 0)
 229                                         script_call("informed");
 230                         }
 231
 232                         continue;
 233                 }
 234
 235                 // Stateful mode
 236                 if (dhcpv6_request(DHCPV6_MSG_REQUEST) < 0)
 237                         continue;
 238
 239                 odhcp6c_signal_process();
 240                 script_call("bound");
 241                 bound = true;
 242                 syslog(LOG_NOTICE, "entering stateful-mode on %s", ifname);
 243
 244                 while (do_signal == 0 || do_signal == SIGUSR1) {
 245                         // Renew Cycle
 246                         // Wait for T1 to expire or until we get a reconfigure
 247                         int res = dhcpv6_poll_reconfigure();
 248                         odhcp6c_signal_process();
 249                         if (res >= 0) {
 250                                 if (res > 0)
 251                                         script_call("updated");
 252
 253                                 continue;
 254                         }
 255
 256                         // Handle signal, if necessary
 257                         if (do_signal == SIGUSR1)
 258                                 do_signal = 0; // Acknowledged
 259                         else if (do_signal > 0)
 260                                 break; // Other signal type
 261
 262                         size_t ia_pd_len, ia_na_len, ia_pd_new, ia_na_new;
 263                         odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 264                         odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 265
 266                         // If we have any IAs, send renew, otherwise request
 267                         int r;
 268                         if (ia_pd_len == 0 && ia_na_len == 0)
 269                                 r = dhcpv6_request(DHCPV6_MSG_REQUEST);
 270                         else
 271                                 r = dhcpv6_request(DHCPV6_MSG_RENEW);
 272                         odhcp6c_signal_process();
 273                         if (r > 0) // Publish updates
 274                                 script_call("updated");
 275                         if (r >= 0)
 276                                 continue; // Renew was successful
 277
 278                         odhcp6c_clear_state(STATE_SERVER_ID); // Remove binding
 279
 280                         // If we have IAs, try rebind otherwise restart
 281                         res = dhcpv6_request(DHCPV6_MSG_REBIND);
 282                         odhcp6c_signal_process();
 283
 284                         odhcp6c_get_state(STATE_IA_PD, &ia_pd_new);
 285                         odhcp6c_get_state(STATE_IA_NA, &ia_na_new);
 286                         if (res < 0 || (ia_pd_new == 0 && ia_pd_len) ||
 287                                         (ia_na_new == 0 && ia_na_len))
 288                                 break; // We lost all our IAs, restart
 289                         else if (res > 0)
 290                                 script_call("rebound");
 291                 }
 292
 293
 294                 size_t ia_pd_len, ia_na_len, server_id_len;
 295                 odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 296                 odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 297                 odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 298
 299                 // Add all prefixes to lost prefixes
 300                 bound = false;
 301                 script_call("unbound");
 302
 303                 if (server_id_len > 0 && (ia_pd_len > 0 || ia_na_len > 0) && release)
 304                         dhcpv6_request(DHCPV6_MSG_RELEASE);
 305
 306                 odhcp6c_clear_state(STATE_IA_NA);
 307                 odhcp6c_clear_state(STATE_IA_PD);
 308         }
 309
 310         script_call("stopped");
 311         return 0;
 312 }
 313
 314
 315 static int usage(void)
 316 {
 317         const char buf[] =
 318         "Usage: odhcp6c [options] <interface>\n"
 319         "\nFeature options:\n"
 320         "       -S <time>       Wait at least <time> sec for a DHCP-server (0)\n"
 321         "       -N <mode>       Mode for requesting addresses [try|force|none]\n"
 322         "       -P <length>     Request IPv6-Prefix (0 = auto)\n"
 323         "       -c <clientid>   Override client-ID (base-16 encoded)\n"
 324         "       -i <iface-id>   Use a custom interface identifier for RA handling\n"
 325         "       -r <options>    Options to be requested (comma-separated)\n"
 326         "       -s <script>     Status update script (/usr/sbin/odhcp6c-update)\n"
 327         "       -k              Don't send a RELEASE when stopping\n"
 328         "\nInvocation options:\n"
 329         "       -p <pidfile>    Set pidfile (/var/run/6relayd.pid)\n"
 330         "       -d              Daemonize\n"
 331         "       -e              Write logmessages to stderr\n"
 332         //"     -v              Increase logging verbosity\n"
 333         "       -h              Show this help\n\n";
 334         write(STDERR_FILENO, buf, sizeof(buf));
 335         return 1;
 336 }
 337
 338
 339 // Don't want to pull-in librt and libpthread just for a monotonic clock...
 340 uint64_t odhcp6c_get_milli_time(void)
 341 {
 342         struct timespec t = {0, 0};
 343         syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &t);
 344         return t.tv_sec * 1000 + t.tv_nsec / 1000000;
 345 }
 346
 347
 348 static uint8_t* odhcp6c_resize_state(enum odhcp6c_state state, ssize_t len)
 349 {
 350         if (len == 0)
 351                 return state_data[state] + state_len[state];
 352         else if (state_len[state] + len > 1024)
 353                 return NULL;
 354
 355         uint8_t *n = realloc(state_data[state], state_len[state] + len);
 356         if (n || state_len[state] + len == 0) {
 357                 state_data[state] = n;
 358                 n += state_len[state];
 359                 state_len[state] += len;
 360         }
 361         return n;
 362 }
 363
 364
 365 bool odhcp6c_signal_process(void)
 366 {
 367         if (do_signal == SIGIO) {
 368                 do_signal = 0;
 369                 bool ra_rtnled = ra_rtnl_process();
 370                 bool ra_updated = ra_process();
 371
 372                 if (ra_rtnled || (ra_updated && (bound || allow_slaac_only == 0)))
 373                         script_call("ra-updated"); // Immediate process urgent events
 374                 else if (ra_updated && !bound && allow_slaac_only > 0)
 375                         script_delay_call("ra-updated", allow_slaac_only);
 376         }
 377
 378         return do_signal != 0;
 379 }
 380
 381
 382 void odhcp6c_clear_state(enum odhcp6c_state state)
 383 {
 384         state_len[state] = 0;
 385 }
 386
 387
 388 void odhcp6c_add_state(enum odhcp6c_state state, const void *data, size_t len)
 389 {
 390         uint8_t *n = odhcp6c_resize_state(state, len);
 391         if (n)
 392                 memcpy(n, data, len);
 393 }
 394
 395
 396 size_t odhcp6c_remove_state(enum odhcp6c_state state, size_t offset, size_t len)
 397 {
 398         uint8_t *data = state_data[state];
 399         ssize_t len_after = state_len[state] - (offset + len);
 400         if (len_after < 0)
 401                 return state_len[state];
 402
 403         memmove(data + offset, data + offset + len, len_after);
 404         return state_len[state] -= len;
 405 }
 406
 407
 408 void* odhcp6c_get_state(enum odhcp6c_state state, size_t *len)
 409 {
 410         *len = state_len[state];
 411         return state_data[state];
 412 }
 413
 414
 415 struct odhcp6c_entry* odhcp6c_find_entry(enum odhcp6c_state state, const struct odhcp6c_entry *new)
 416 {
 417         size_t len, cmplen = offsetof(struct odhcp6c_entry, target) + new->length / 8;
 418         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 419         struct odhcp6c_entry *x = NULL;
 420
 421         for (struct odhcp6c_entry *c = start; !x && c < &start[len/sizeof(*c)]; ++c)
 422                 if (!memcmp(c, new, cmplen))
 423                         return c;
 424
 425         return NULL;
 426 }
 427
 428
 429 void odhcp6c_update_entry_safe(enum odhcp6c_state state, struct odhcp6c_entry *new, uint32_t safe)
 430 {
 431         size_t len;
 432         struct odhcp6c_entry *x = odhcp6c_find_entry(state, new);
 433         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 434
 435         if (x && x->valid > new->valid && new->valid < safe)
 436                 new->valid = safe;
 437
 438         if (new->valid > 0) {
 439                 if (x) {
 440                         x->valid = new->valid;
 441                         x->preferred = new->preferred;
 442                 } else {
 443                         odhcp6c_add_state(state, new, sizeof(*new));
 444                 }
 445         } else if (x) {
 446                 odhcp6c_remove_state(state, (x - start) * sizeof(*x), sizeof(*x));
 447         }
 448 }
 449
 450
 451 void odhcp6c_update_entry(enum odhcp6c_state state, struct odhcp6c_entry *new)
 452 {
 453         odhcp6c_update_entry_safe(state, new, 0);
 454 }
 455
 456
 457 static void odhcp6c_expire_list(enum odhcp6c_state state, uint32_t elapsed)
 458 {
 459         size_t len;
 460         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 461         for (struct odhcp6c_entry *c = start; c < &start[len / sizeof(*c)]; ++c) {
 462                 if (c->preferred < elapsed)
 463                         c->preferred = 0;
 464                 else if (c->preferred != UINT32_MAX)
 465                         c->preferred -= elapsed;
 466
 467                 if (c->valid < elapsed)
 468                         c->valid = 0;
 469                 else if (c->valid != UINT32_MAX)
 470                         c->valid -= elapsed;
 471
 472                 if (!c->valid)
 473                         odhcp6c_remove_state(state, (c - start) * sizeof(*c), sizeof(*c));
 474         }
 475 }
 476
 477
 478 void odhcp6c_expire(void)
 479 {
 480         time_t now = odhcp6c_get_milli_time() / 1000;
 481         uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 482         last_update = now;
 483
 484         odhcp6c_expire_list(STATE_RA_PREFIX, elapsed);
 485         odhcp6c_expire_list(STATE_RA_ROUTE, elapsed);
 486         odhcp6c_expire_list(STATE_RA_DNS, elapsed);
 487         odhcp6c_expire_list(STATE_IA_NA, elapsed);
 488         odhcp6c_expire_list(STATE_IA_PD, elapsed);
 489 }
 490
 491
 492 uint32_t odhcp6c_elapsed(void)
 493 {
 494         return odhcp6c_get_milli_time() / 1000 - last_update;
 495 }
 496
 497
 498 void odhcp6c_random(void *buf, size_t len)
 499 {
 500         read(urandom_fd, buf, len);
 501 }
 502
 503
 504 static void sighandler(int signal)
 505 {
 506         if (signal == SIGCHLD)
 507                 while (waitpid(-1, NULL, WNOHANG) > 0);
 508         else if (signal == SIGUSR1)
 509                 do_signal = SIGUSR1;
 510         else if (signal == SIGUSR2)
 511                 do_signal = SIGUSR2;
 512         else if (signal == SIGIO)
 513                 do_signal = SIGIO;
 514         else
 515                 do_signal = SIGTERM;
 516 }