src/odhcp6c.c

   1 /**
   2  * Copyright (C) 2012 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;
  44 static bool bound = false;
  45
  46
  47 int main(_unused int argc, char* const argv[])
  48 {
  49         openlog("odhcp6c", LOG_PERROR | LOG_PID, LOG_DAEMON);
  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
  60         bool help = false, daemonize = false;
  61         int c, request_pd = 0;
  62         while ((c = getopt(argc, argv, "N:P:c:r:s:hdp:")) != -1) {
  63                 switch (c) {
  64                 case 'N':
  65                         if (!strcmp(optarg, "force"))
  66                                 ia_na_mode = IA_MODE_FORCE;
  67                         else if (!strcmp(optarg, "none"))
  68                                 ia_na_mode = IA_MODE_NONE;
  69                         else if (!strcmp(optarg, "try"))
  70                                 ia_na_mode = IA_MODE_TRY;
  71                         else
  72                                 help = true;
  73                         break;
  74
  75                 case 'P':
  76                         request_pd = strtoul(optarg, NULL, 10);
  77                         if (request_pd == 0)
  78                                 request_pd = -1;
  79                         break;
  80
  81                 case 'c':
  82                         l = script_unhexlify(&buf[4], sizeof(buf) - 4, optarg);
  83                         if (l > 0) {
  84                                 buf[0] = 0;
  85                                 buf[1] = DHCPV6_OPT_CLIENTID;
  86                                 buf[2] = 0;
  87                                 buf[4] = l;
  88                                 odhcp6c_add_state(STATE_CLIENT_ID, buf, l + 4);
  89                         } else {
  90                                 help = true;
  91                         }
  92                         break;
  93
  94                 case 'r':
  95                         optpos = optarg;
  96                         while (optpos[0]) {
  97                                 opttype = htons(strtoul(optarg, &optpos, 10));
  98                                 if (optpos == optarg)
  99                                         break;
 100                                 else if (optpos[0])
 101                                         optarg = &optpos[1];
 102                                 odhcp6c_add_state(STATE_ORO, &opttype, 2);
 103                         }
 104                         break;
 105
 106                 case 's':
 107                         script = optarg;
 108                         break;
 109
 110                 case 'd':
 111                         daemonize = true;
 112                         break;
 113
 114                 case 'p':
 115                         pidfile = optarg;
 116                         break;
 117
 118                 default:
 119                         help = true;
 120                         break;
 121                 }
 122         }
 123
 124         const char *ifname = argv[optind];
 125
 126         if (help || !ifname)
 127                 return usage();
 128
 129         if ((urandom_fd = open("/dev/urandom", O_CLOEXEC | O_RDONLY)) < 0 ||
 130                         init_dhcpv6(ifname, request_pd) || ra_init(ifname) ||
 131                         script_init(script, ifname)) {
 132                 syslog(LOG_ERR, "failed to initialize: %s", strerror(errno));
 133                 return 3;
 134         }
 135
 136         signal(SIGIO, sighandler);
 137         signal(SIGHUP, sighandler);
 138         signal(SIGINT, sighandler);
 139         signal(SIGCHLD, sighandler);
 140         signal(SIGTERM, sighandler);
 141         signal(SIGUSR1, sighandler);
 142         signal(SIGUSR2, sighandler);
 143
 144         if (daemonize) {
 145                 openlog("odhcp6c", LOG_PID, LOG_DAEMON); // Disable LOG_PERROR
 146                 if (daemon(0, 0)) {
 147                         syslog(LOG_ERR, "Failed to daemonize: %s",
 148                                         strerror(errno));
 149                         return 4;
 150                 }
 151
 152                 char pidbuf[128];
 153                 if (!pidfile) {
 154                         snprintf(pidbuf, sizeof(pidbuf),
 155                                         "/var/run/odhcp6c.%s.pid", ifname);
 156                         pidfile = pidbuf;
 157                 }
 158
 159                 int fd = open(pidfile, O_WRONLY | O_CREAT);
 160                 if (fd >= 0) {
 161                         char buf[8];
 162                         int len = snprintf(buf, sizeof(buf), "%i\n", getpid());
 163                         write(fd, buf, len);
 164                         close(fd);
 165                 }
 166         }
 167
 168         script_call("started");
 169
 170         while (do_signal != SIGTERM) { // Main logic
 171                 odhcp6c_clear_state(STATE_SERVER_ID);
 172                 odhcp6c_clear_state(STATE_SERVER_CAND);
 173                 odhcp6c_clear_state(STATE_IA_PD);
 174                 odhcp6c_clear_state(STATE_SNTP_IP);
 175                 odhcp6c_clear_state(STATE_SNTP_FQDN);
 176                 odhcp6c_clear_state(STATE_SIP_IP);
 177                 odhcp6c_clear_state(STATE_SIP_FQDN);
 178                 dhcpv6_set_ia_na_mode(ia_na_mode);
 179                 bound = false;
 180
 181                 do_signal = 0;
 182                 int res = dhcpv6_request(DHCPV6_MSG_SOLICIT);
 183
 184                 if (res < 0) {
 185                         continue; // Might happen if we got a signal
 186                 } else if (res == DHCPV6_STATELESS) { // Stateless mode
 187                         while (do_signal == 0 || do_signal == SIGUSR1) {
 188                                 do_signal = 0;
 189
 190                                 res = dhcpv6_request(DHCPV6_MSG_INFO_REQ);
 191                                 if (do_signal == SIGUSR1)
 192                                         continue;
 193                                 else if (res < 0)
 194                                         break;
 195                                 else if (res > 0)
 196                                         script_call("informed");
 197
 198                                 bound = true;
 199
 200                                 if (dhcpv6_poll_reconfigure() > 0)
 201                                         script_call("informed");
 202                         }
 203
 204                         continue;
 205                 }
 206
 207                 // Stateful mode
 208                 if (dhcpv6_request(DHCPV6_MSG_REQUEST) < 0)
 209                         continue;
 210
 211                 script_call("bound");
 212                 bound = true;
 213
 214                 while (do_signal == 0 || do_signal == SIGUSR1) {
 215                         // Renew Cycle
 216                         // Wait for T1 to expire or until we get a reconfigure
 217                         int res = dhcpv6_poll_reconfigure();
 218                         if (res >= 0) {
 219                                 if (res > 0)
 220                                         script_call("updated");
 221
 222                                 continue;
 223                         }
 224
 225                         // Handle signal, if necessary
 226                         if (do_signal == SIGUSR1)
 227                                 do_signal = 0; // Acknowledged
 228                         else if (do_signal > 0)
 229                                 break; // Other signal type
 230
 231                         size_t ia_pd_len, ia_na_len, ia_pd_new, ia_na_new;
 232                         odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 233                         odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 234
 235                         // If we have any IAs, send renew, otherwise request
 236                         int r;
 237                         if (ia_pd_len == 0 && ia_na_len == 0)
 238                                 r = dhcpv6_request(DHCPV6_MSG_REQUEST);
 239                         else
 240                                 r = dhcpv6_request(DHCPV6_MSG_RENEW);
 241                         if (r > 0) // Publish updates
 242                                 script_call("updated");
 243                         if (r >= 0)
 244                                 continue; // Renew was successful
 245
 246                         odhcp6c_clear_state(STATE_SERVER_ID); // Remove binding
 247
 248                         // If we have IAs, try rebind otherwise restart
 249                         res = dhcpv6_request(DHCPV6_MSG_REBIND);
 250
 251                         odhcp6c_get_state(STATE_IA_PD, &ia_pd_new);
 252                         odhcp6c_get_state(STATE_IA_NA, &ia_na_new);
 253                         if (res < 0 || (ia_pd_new == 0 && ia_pd_len) ||
 254                                         (ia_na_new == 0 && ia_na_len))
 255                                 break; // We lost all our IAs, restart
 256                         else if (res > 0)
 257                                 script_call("rebound");
 258                 }
 259
 260
 261                 size_t ia_pd_len, ia_na_len, server_id_len;
 262                 odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 263                 odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 264                 odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 265
 266                 // Add all prefixes to lost prefixes
 267                 bound = false;
 268                 script_call("unbound");
 269
 270                 if (server_id_len > 0 && (ia_pd_len > 0 || ia_na_len > 0))
 271                         dhcpv6_request(DHCPV6_MSG_RELEASE);
 272
 273                 odhcp6c_clear_state(STATE_IA_NA);
 274                 odhcp6c_clear_state(STATE_IA_PD);
 275         }
 276
 277         script_call("stopped");
 278         return 0;
 279 }
 280
 281
 282 static int usage(void)
 283 {
 284         const char buf[] =
 285         "Usage: odhcp6c [options] <interface>\n"
 286         "\nFeature options:\n"
 287         "       -N <mode>       Mode for requesting addresses [try|force|none]\n"
 288         "       -P <length>     Request IPv6-Prefix (0 = auto)\n"
 289         "       -c <clientid>   Override client-ID (base-16 encoded)\n"
 290         "       -r <options>    Options to be requested (comma-separated)\n"
 291         "       -s <script>     Status update script (/usr/sbin/odhcp6c-update)\n"
 292         "\nInvocation options:\n"
 293         "       -p <pidfile>    Set pidfile (/var/run/6relayd.pid)\n"
 294         "       -d              Daemonize\n"
 295         //"     -v              Increase logging verbosity\n"
 296         "       -h              Show this help\n\n";
 297         write(STDERR_FILENO, buf, sizeof(buf));
 298         return 1;
 299 }
 300
 301
 302 // Don't want to pull-in librt and libpthread just for a monotonic clock...
 303 uint64_t odhcp6c_get_milli_time(void)
 304 {
 305         struct timespec t = {0, 0};
 306         syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &t);
 307         return t.tv_sec * 1000 + t.tv_nsec / 1000000;
 308 }
 309
 310
 311 static uint8_t* odhcp6c_resize_state(enum odhcp6c_state state, ssize_t len)
 312 {
 313         if (len == 0)
 314                 return state_data[state] + state_len[state];
 315
 316         uint8_t *n = realloc(state_data[state], state_len[state] + len);
 317         if (n || state_len[state] + len == 0) {
 318                 state_data[state] = n;
 319                 n += state_len[state];
 320                 state_len[state] += len;
 321         }
 322         return n;
 323 }
 324
 325
 326 bool odhcp6c_signal_process(void)
 327 {
 328         if (do_signal == SIGIO) {
 329                 do_signal = 0;
 330                 bool updated = ra_process();
 331                 updated |= ra_rtnl_process();
 332                 if (updated && bound) {
 333                         odhcp6c_expire();
 334                         script_call("ra-updated");
 335                 }
 336         }
 337
 338         return do_signal != 0;
 339 }
 340
 341
 342 void odhcp6c_clear_state(enum odhcp6c_state state)
 343 {
 344         state_len[state] = 0;
 345 }
 346
 347
 348 void odhcp6c_add_state(enum odhcp6c_state state, const void *data, size_t len)
 349 {
 350         uint8_t *n = odhcp6c_resize_state(state, len);
 351         if (n)
 352                 memcpy(n, data, len);
 353 }
 354
 355
 356 size_t odhcp6c_remove_state(enum odhcp6c_state state, size_t offset, size_t len)
 357 {
 358         uint8_t *data = state_data[state];
 359         ssize_t len_after = state_len[state] - (offset + len);
 360         if (len_after < 0)
 361                 return state_len[state];
 362
 363         memmove(data + offset, data + offset + len, len_after);
 364         return state_len[state] -= len;
 365 }
 366
 367
 368 void* odhcp6c_get_state(enum odhcp6c_state state, size_t *len)
 369 {
 370         *len = state_len[state];
 371         return state_data[state];
 372 }
 373
 374
 375 struct odhcp6c_entry* odhcp6c_find_entry(enum odhcp6c_state state, const struct odhcp6c_entry *new)
 376 {
 377         size_t len, cmplen = offsetof(struct odhcp6c_entry, target) + new->length / 8;
 378         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 379         struct odhcp6c_entry *x = NULL;
 380
 381         for (struct odhcp6c_entry *c = start; !x && c < &start[len/sizeof(*c)]; ++c)
 382                 if (!memcmp(c, new, cmplen))
 383                         return c;
 384
 385         return NULL;
 386 }
 387
 388
 389 void odhcp6c_update_entry_safe(enum odhcp6c_state state, const struct odhcp6c_entry *new, uint32_t safe)
 390 {
 391         size_t len;
 392         struct odhcp6c_entry *x = odhcp6c_find_entry(state, new);
 393         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 394
 395         if (x && x->valid > new->valid && new->valid < safe)
 396                 return;
 397
 398         if (new->valid > 0) {
 399                 if (x)
 400                         *x = *new;
 401                 else
 402                         odhcp6c_add_state(state, new, sizeof(*new));
 403         } else if (x) {
 404                 odhcp6c_remove_state(state, (x - start) * sizeof(*x), sizeof(*x));
 405         }
 406 }
 407
 408
 409 void odhcp6c_update_entry(enum odhcp6c_state state, const struct odhcp6c_entry *new)
 410 {
 411         odhcp6c_update_entry_safe(state, new, 0);
 412 }
 413
 414
 415 static void odhcp6c_expire_list(enum odhcp6c_state state, uint32_t elapsed)
 416 {
 417         size_t len;
 418         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 419         for (struct odhcp6c_entry *c = start; c < &start[len / sizeof(*c)]; ++c) {
 420                 if (c->preferred < elapsed)
 421                         c->preferred = 0;
 422                 else if (c->preferred != UINT32_MAX)
 423                         c->preferred -= elapsed;
 424
 425                 if (c->valid < elapsed)
 426                         c->valid = 0;
 427                 else if (c->valid != UINT32_MAX)
 428                         c->valid -= elapsed;
 429
 430                 if (!c->valid)
 431                         odhcp6c_remove_state(state, (c - start) * sizeof(*c), sizeof(*c));
 432         }
 433 }
 434
 435
 436 void odhcp6c_expire(void)
 437 {
 438         static time_t last_update = 0;
 439         time_t now = odhcp6c_get_milli_time() / 1000;
 440
 441         uint32_t elapsed = now - last_update;
 442         last_update = now;
 443
 444         odhcp6c_expire_list(STATE_RA_PREFIX, elapsed);
 445         odhcp6c_expire_list(STATE_RA_ROUTE, elapsed);
 446         odhcp6c_expire_list(STATE_IA_NA, elapsed);
 447         odhcp6c_expire_list(STATE_IA_PD, elapsed);
 448 }
 449
 450
 451 void odhcp6c_random(void *buf, size_t len)
 452 {
 453         read(urandom_fd, buf, len);
 454 }
 455
 456
 457 static void sighandler(int signal)
 458 {
 459         if (signal == SIGCHLD)
 460                 while (waitpid(-1, NULL, WNOHANG) > 0);
 461         else if (signal == SIGUSR1)
 462                 do_signal = SIGUSR1;
 463         else if (signal == SIGUSR2)
 464                 do_signal = SIGUSR2;
 465         else if (signal == SIGIO)
 466                 do_signal = SIGIO;
 467         else
 468                 do_signal = SIGTERM;
 469 }