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 <unistd.h>
  21 #include <syslog.h>
  22 #include <signal.h>
  23 #include <string.h>
  24 #include <stdbool.h>
  25
  26 #include <net/if.h>
  27 #include <sys/wait.h>
  28 #include <sys/syscall.h>
  29
  30 #include "odhcp6c.h"
  31
  32
  33 static void sighandler(int signal);
  34 static int usage(void);
  35
  36
  37 static uint8_t *state_data[_STATE_MAX] = {NULL};
  38 static size_t state_len[_STATE_MAX] = {0};
  39
  40 static volatile int do_signal = 0;
  41
  42
  43 int main(_unused int argc, char* const argv[])
  44 {
  45         openlog("odhcp6c", LOG_PERROR | LOG_PID, LOG_DAEMON);
  46
  47         // Allocate ressources
  48         const char *pidfile = NULL;
  49         const char *script = "/usr/sbin/odhcp6c-update";
  50         ssize_t l;
  51         uint8_t buf[134];
  52         char *optpos;
  53         uint16_t opttype;
  54         enum odhcp6c_ia_mode ia_na_mode = IA_MODE_TRY;
  55
  56         bool help = false, daemonize = false;
  57         int c, request_pd = 0, timeout = 0;
  58         while ((c = getopt(argc, argv, "N:P:c:r:s:t:hdp:")) != -1) {
  59                 switch (c) {
  60                 case 'N':
  61                         if (!strcmp(optarg, "force"))
  62                                 ia_na_mode = IA_MODE_FORCE;
  63                         else if (!strcmp(optarg, "none"))
  64                                 ia_na_mode = IA_MODE_NONE;
  65                         else if (!strcmp(optarg, "try"))
  66                                 ia_na_mode = IA_MODE_TRY;
  67                         else
  68                                 help = true;
  69                         break;
  70
  71                 case 'P':
  72                         request_pd = strtoul(optarg, NULL, 10);
  73                         if (request_pd == 0)
  74                                 request_pd = -1;
  75                         break;
  76
  77                 case 'c':
  78                         l = script_unhexlify(&buf[4], sizeof(buf) - 4, optarg);
  79                         if (l > 0) {
  80                                 buf[0] = 0;
  81                                 buf[1] = DHCPV6_OPT_CLIENTID;
  82                                 buf[2] = 0;
  83                                 buf[4] = l;
  84                                 odhcp6c_add_state(STATE_CLIENT_ID, buf, l + 4);
  85                         } else {
  86                                 help = true;
  87                         }
  88                         break;
  89
  90                 case 'r':
  91                         optpos = optarg;
  92                         while (optpos[0]) {
  93                                 opttype = htons(strtoul(optarg, &optpos, 10));
  94                                 if (optpos == optarg)
  95                                         break;
  96                                 else if (optpos[0])
  97                                         optarg = &optpos[1];
  98                                 odhcp6c_add_state(STATE_ORO, &opttype, 2);
  99                         }
 100                         break;
 101
 102                 case 's':
 103                         script = optarg;
 104                         break;
 105
 106                 case 't':
 107                         timeout = strtoul(optarg, NULL, 10);
 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 (init_dhcpv6(ifname, request_pd) || init_rtnetlink() ||
 130                         script_init(script, ifname)) {
 131                 syslog(LOG_ERR, "failed to initialize: %s", strerror(errno));
 132                 return 3;
 133         }
 134
 135         signal(SIGHUP, sighandler);
 136         signal(SIGINT, sighandler);
 137         signal(SIGALRM, sighandler);
 138         signal(SIGCHLD, sighandler);
 139         signal(SIGTERM, sighandler);
 140         signal(SIGUSR1, sighandler);
 141         signal(SIGUSR2, sighandler);
 142
 143         if (daemonize) {
 144                 openlog("odhcp6c", LOG_PID, LOG_DAEMON); // Disable LOG_PERROR
 145                 if (daemon(0, 0)) {
 146                         syslog(LOG_ERR, "Failed to daemonize: %s",
 147                                         strerror(errno));
 148                         return 4;
 149                 }
 150
 151                 char pidbuf[128];
 152                 if (!pidfile) {
 153                         snprintf(pidbuf, sizeof(pidbuf),
 154                                         "/var/run/odhcp6c.%s.pid", ifname);
 155                         pidfile = pidbuf;
 156                 }
 157
 158                 int fd = open(pidfile, O_WRONLY | O_CREAT);
 159                 if (fd >= 0) {
 160                         char buf[8];
 161                         int len = snprintf(buf, sizeof(buf), "%i\n", getpid());
 162                         write(fd, buf, len);
 163                         close(fd);
 164                 }
 165         }
 166
 167         while (do_signal != SIGTERM) { // Main logic
 168                 odhcp6c_clear_state(STATE_SERVER_ID);
 169                 odhcp6c_clear_state(STATE_SERVER_CAND);
 170                 odhcp6c_clear_state(STATE_IA_PD);
 171                 odhcp6c_clear_state(STATE_IA_PD_LOST);
 172                 dhcpv6_set_ia_na_mode(ia_na_mode);
 173
 174                 alarm(timeout);
 175                 do_signal = 0;
 176                 int res = dhcpv6_request(DHCPV6_MSG_SOLICIT);
 177
 178                 if (res < 0) {
 179                         continue; // Might happen if we got a signal
 180                 } else if (res == DHCPV6_STATELESS) { // Stateless mode
 181                         while (do_signal == 0 || do_signal == SIGUSR1) {
 182                                 do_signal = 0;
 183
 184                                 res = dhcpv6_request(DHCPV6_MSG_INFO_REQ);
 185                                 if (do_signal == SIGUSR1)
 186                                         continue;
 187                                 else if (res < 0)
 188                                         break;
 189                                 else if (res > 0)
 190                                         script_call("informed");
 191
 192                                 alarm(0);
 193                                 if (dhcpv6_poll_reconfigure() > 0)
 194                                         script_call("informed");
 195                         }
 196
 197                         if (do_signal == SIGALRM)
 198                                 script_call("timeout");
 199
 200                         continue;
 201                 }
 202
 203                 // Stateful mode
 204                 if (dhcpv6_request(DHCPV6_MSG_REQUEST) < 0)
 205                         continue;
 206
 207                 script_call("bound");
 208                 alarm(0);
 209
 210                 while (do_signal == 0 || do_signal == SIGUSR1) {
 211                         // Renew Cycle
 212                         // Wait for T1 to expire or until we get a reconfigure
 213                         int res = dhcpv6_poll_reconfigure();
 214                         if (res >= 0) {
 215                                 if (res > 0)
 216                                         script_call("updated");
 217
 218                                 continue;
 219                         }
 220
 221                         // Handle signal, if necessary
 222                         if (do_signal == SIGUSR1)
 223                                 do_signal = 0; // Acknowledged
 224                         else if (do_signal > 0)
 225                                 break; // Other signal type
 226
 227                         size_t ia_pd_len, ia_na_len, ia_pd_new, ia_na_new;
 228                         odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 229                         odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 230
 231                         // If we have any IAs, send renew, otherwise request
 232                         int r;
 233                         if (ia_pd_len == 0 && ia_na_len == 0)
 234                                 r = dhcpv6_request(DHCPV6_MSG_REQUEST);
 235                         else
 236                                 r = dhcpv6_request(DHCPV6_MSG_RENEW);
 237                         if (r > 0) // Publish updates
 238                                 script_call("updated");
 239                         if (r >= 0)
 240                                 continue; // Renew was successful
 241
 242                         odhcp6c_clear_state(STATE_SERVER_ID); // Remove binding
 243
 244                         // If we have IAs, try rebind otherwise restart
 245                         res = dhcpv6_request(DHCPV6_MSG_REBIND);
 246
 247                         odhcp6c_get_state(STATE_IA_PD, &ia_pd_new);
 248                         odhcp6c_get_state(STATE_IA_NA, &ia_na_new);
 249                         if (res < 0 || (ia_pd_new == 0 && ia_pd_len) ||
 250                                         (ia_na_new == 0 && ia_na_len))
 251                                 break; // We lost all our IAs, restart
 252                         else if (res > 0)
 253                                 script_call("rebound");
 254                 }
 255
 256
 257                 size_t ia_pd_len, ia_na_len, server_id_len;
 258                 uint8_t *ia_pd = odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 259                 odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 260                 odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 261
 262                 // Add all prefixes to lost prefixes
 263                 odhcp6c_add_state(STATE_IA_PD_LOST, ia_pd, ia_pd_len);
 264                 odhcp6c_clear_state(STATE_IA_PD);
 265
 266                 if (do_signal == SIGALRM)
 267                         script_call("timeout");
 268                 else
 269                         script_call("unbound");
 270
 271                 // Remove assigned addresses
 272                 if (ia_na_len > 0)
 273                         dhcpv6_remove_addrs();
 274
 275                 if (server_id_len > 0 && (ia_pd_len > 0 || ia_na_len > 0))
 276                         dhcpv6_request(DHCPV6_MSG_RELEASE);
 277         }
 278
 279         return 0;
 280 }
 281
 282
 283 static int usage(void)
 284 {
 285         const char buf[] =
 286         "Usage: odhcp6c [options] <interface>\n"
 287         "\nFeature options:\n"
 288         "       -N <mode>       Mode for requesting addresses [try|force|none]\n"
 289         "       -P <length>     Request IPv6-Prefix (0 = auto)\n"
 290         "       -c <clientid>   Override client-ID (base-16 encoded)\n"
 291         "       -r <options>    Options to be requested (comma-separated)\n"
 292         "       -s <script>     Status update script (/usr/sbin/odhcp6c-update)\n"
 293         "       -t <timeout>    Request timeout after which the script is called\n"
 294         "\nInvocation options:\n"
 295         "       -p <pidfile>    Set pidfile (/var/run/6relayd.pid)\n"
 296         "       -d              Daemonize\n"
 297         //"     -v              Increase logging verbosity\n"
 298         "       -h              Show this help\n\n";
 299         write(STDERR_FILENO, buf, sizeof(buf));
 300         return 1;
 301 }
 302
 303
 304 // Don't want to pull-in librt and libpthread just for a monotonic clock...
 305 uint64_t odhcp6c_get_milli_time(void)
 306 {
 307         struct timespec t = {0, 0};
 308         syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &t);
 309         return t.tv_sec * 1000 + t.tv_nsec / 1000000;
 310 }
 311
 312
 313 static uint8_t* odhcp6c_resize_state(enum odhcp6c_state state, ssize_t len)
 314 {
 315         if (len == 0)
 316                 return state_data[state] + state_len[state];
 317
 318         uint8_t *n = realloc(state_data[state], state_len[state] + len);
 319         if (n || state_len[state] + len == 0) {
 320                 state_data[state] = n;
 321                 n += state_len[state];
 322                 state_len[state] += len;
 323         }
 324         return n;
 325 }
 326
 327
 328 bool odhcp6c_signal_is_pending(void)
 329 {
 330         return do_signal != 0;
 331 }
 332
 333
 334 void odhcp6c_clear_state(enum odhcp6c_state state)
 335 {
 336         state_len[state] = 0;
 337 }
 338
 339
 340 void odhcp6c_add_state(enum odhcp6c_state state, const void *data, size_t len)
 341 {
 342         uint8_t *n = odhcp6c_resize_state(state, len);
 343         if (n)
 344                 memcpy(n, data, len);
 345 }
 346
 347
 348 size_t odhcp6c_remove_state(enum odhcp6c_state state, size_t offset, size_t len)
 349 {
 350         uint8_t *data = state_data[state];
 351         ssize_t len_after = state_len[state] - (offset + len);
 352         if (len_after < 0)
 353                 return state_len[state];
 354
 355         memmove(data + offset, data + offset + len, len_after);
 356         return state_len[state] -= len;
 357 }
 358
 359
 360 bool odhcp6c_commit_state(enum odhcp6c_state state, size_t old_len)
 361 {
 362         size_t new_len = state_len[state] - old_len;
 363         uint8_t *old_data = state_data[state], *new_data = old_data + old_len;
 364         bool upd = new_len != old_len || memcmp(old_data, new_data, new_len);
 365
 366         memmove(old_data, new_data, new_len);
 367         odhcp6c_resize_state(state, -old_len);
 368
 369         return upd;
 370 }
 371
 372
 373 void* odhcp6c_get_state(enum odhcp6c_state state, size_t *len)
 374 {
 375         *len = state_len[state];
 376         return state_data[state];
 377 }
 378
 379
 380 static void sighandler(int signal)
 381 {
 382         if (signal == SIGCHLD)
 383                 while (waitpid(-1, NULL, WNOHANG) > 0);
 384         else if (signal == SIGUSR1)
 385                 do_signal = SIGUSR1;
 386         else if (signal == SIGUSR2)
 387                 do_signal = SIGUSR2;
 388         else if (signal == SIGALRM)
 389                 do_signal = SIGALRM;
 390         else
 391                 do_signal = SIGTERM;
 392 }