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;
  58         while ((c = getopt(argc, argv, "N:P:c:r:s: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 'd':
 107                         daemonize = true;
 108                         break;
 109
 110                 case 'p':
 111                         pidfile = optarg;
 112                         break;
 113
 114                 default:
 115                         help = true;
 116                         break;
 117                 }
 118         }
 119
 120         const char *ifname = argv[optind];
 121
 122         if (help || !ifname)
 123                 return usage();
 124
 125         if (init_dhcpv6(ifname, request_pd) || init_rtnetlink() ||
 126                         script_init(script, ifname)) {
 127                 syslog(LOG_ERR, "failed to initialize: %s", strerror(errno));
 128                 return 3;
 129         }
 130
 131         signal(SIGHUP, sighandler);
 132         signal(SIGINT, sighandler);
 133         signal(SIGCHLD, sighandler);
 134         signal(SIGTERM, sighandler);
 135         signal(SIGUSR1, sighandler);
 136         signal(SIGUSR2, sighandler);
 137
 138         if (daemonize) {
 139                 openlog("odhcp6c", LOG_PID, LOG_DAEMON); // Disable LOG_PERROR
 140                 if (daemon(0, 0)) {
 141                         syslog(LOG_ERR, "Failed to daemonize: %s",
 142                                         strerror(errno));
 143                         return 4;
 144                 }
 145
 146                 char pidbuf[128];
 147                 if (!pidfile) {
 148                         snprintf(pidbuf, sizeof(pidbuf),
 149                                         "/var/run/odhcp6c.%s.pid", ifname);
 150                         pidfile = pidbuf;
 151                 }
 152
 153                 int fd = open(pidfile, O_WRONLY | O_CREAT);
 154                 if (fd >= 0) {
 155                         char buf[8];
 156                         int len = snprintf(buf, sizeof(buf), "%i\n", getpid());
 157                         write(fd, buf, len);
 158                         close(fd);
 159                 }
 160         }
 161
 162         script_call("started");
 163
 164         while (do_signal != SIGTERM) { // Main logic
 165                 odhcp6c_clear_state(STATE_SERVER_ID);
 166                 odhcp6c_clear_state(STATE_SERVER_CAND);
 167                 odhcp6c_clear_state(STATE_IA_PD);
 168                 odhcp6c_clear_state(STATE_SNTP_IP);
 169                 odhcp6c_clear_state(STATE_SNTP_FQDN);
 170                 odhcp6c_clear_state(STATE_SIP_IP);
 171                 odhcp6c_clear_state(STATE_SIP_FQDN);
 172                 dhcpv6_set_ia_na_mode(ia_na_mode);
 173
 174                 do_signal = 0;
 175                 int res = dhcpv6_request(DHCPV6_MSG_SOLICIT);
 176
 177                 if (res < 0) {
 178                         continue; // Might happen if we got a signal
 179                 } else if (res == DHCPV6_STATELESS) { // Stateless mode
 180                         while (do_signal == 0 || do_signal == SIGUSR1) {
 181                                 do_signal = 0;
 182
 183                                 res = dhcpv6_request(DHCPV6_MSG_INFO_REQ);
 184                                 if (do_signal == SIGUSR1)
 185                                         continue;
 186                                 else if (res < 0)
 187                                         break;
 188                                 else if (res > 0)
 189                                         script_call("informed");
 190
 191                                 if (dhcpv6_poll_reconfigure() > 0)
 192                                         script_call("informed");
 193                         }
 194
 195                         continue;
 196                 }
 197
 198                 // Stateful mode
 199                 if (dhcpv6_request(DHCPV6_MSG_REQUEST) < 0)
 200                         continue;
 201
 202                 script_call("bound");
 203
 204                 while (do_signal == 0 || do_signal == SIGUSR1) {
 205                         // Renew Cycle
 206                         // Wait for T1 to expire or until we get a reconfigure
 207                         int res = dhcpv6_poll_reconfigure();
 208                         if (res >= 0) {
 209                                 if (res > 0)
 210                                         script_call("updated");
 211
 212                                 continue;
 213                         }
 214
 215                         // Handle signal, if necessary
 216                         if (do_signal == SIGUSR1)
 217                                 do_signal = 0; // Acknowledged
 218                         else if (do_signal > 0)
 219                                 break; // Other signal type
 220
 221                         size_t ia_pd_len, ia_na_len, ia_pd_new, ia_na_new;
 222                         odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 223                         odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 224
 225                         // If we have any IAs, send renew, otherwise request
 226                         int r;
 227                         if (ia_pd_len == 0 && ia_na_len == 0)
 228                                 r = dhcpv6_request(DHCPV6_MSG_REQUEST);
 229                         else
 230                                 r = dhcpv6_request(DHCPV6_MSG_RENEW);
 231                         if (r > 0) // Publish updates
 232                                 script_call("updated");
 233                         if (r >= 0)
 234                                 continue; // Renew was successful
 235
 236                         odhcp6c_clear_state(STATE_SERVER_ID); // Remove binding
 237
 238                         // If we have IAs, try rebind otherwise restart
 239                         res = dhcpv6_request(DHCPV6_MSG_REBIND);
 240
 241                         odhcp6c_get_state(STATE_IA_PD, &ia_pd_new);
 242                         odhcp6c_get_state(STATE_IA_NA, &ia_na_new);
 243                         if (res < 0 || (ia_pd_new == 0 && ia_pd_len) ||
 244                                         (ia_na_new == 0 && ia_na_len))
 245                                 break; // We lost all our IAs, restart
 246                         else if (res > 0)
 247                                 script_call("rebound");
 248                 }
 249
 250
 251                 size_t ia_pd_len, ia_na_len, server_id_len;
 252                 odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 253                 odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 254                 odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 255
 256                 // Add all prefixes to lost prefixes
 257                 odhcp6c_clear_state(STATE_IA_PD);
 258                 script_call("unbound");
 259
 260                 // Remove assigned addresses
 261                 if (ia_na_len > 0)
 262                         dhcpv6_remove_addrs();
 263
 264                 if (server_id_len > 0 && (ia_pd_len > 0 || ia_na_len > 0))
 265                         dhcpv6_request(DHCPV6_MSG_RELEASE);
 266         }
 267
 268         script_call("stopped");
 269         return 0;
 270 }
 271
 272
 273 static int usage(void)
 274 {
 275         const char buf[] =
 276         "Usage: odhcp6c [options] <interface>\n"
 277         "\nFeature options:\n"
 278         "       -N <mode>       Mode for requesting addresses [try|force|none]\n"
 279         "       -P <length>     Request IPv6-Prefix (0 = auto)\n"
 280         "       -c <clientid>   Override client-ID (base-16 encoded)\n"
 281         "       -r <options>    Options to be requested (comma-separated)\n"
 282         "       -s <script>     Status update script (/usr/sbin/odhcp6c-update)\n"
 283         "\nInvocation options:\n"
 284         "       -p <pidfile>    Set pidfile (/var/run/6relayd.pid)\n"
 285         "       -d              Daemonize\n"
 286         //"     -v              Increase logging verbosity\n"
 287         "       -h              Show this help\n\n";
 288         write(STDERR_FILENO, buf, sizeof(buf));
 289         return 1;
 290 }
 291
 292
 293 // Don't want to pull-in librt and libpthread just for a monotonic clock...
 294 uint64_t odhcp6c_get_milli_time(void)
 295 {
 296         struct timespec t = {0, 0};
 297         syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &t);
 298         return t.tv_sec * 1000 + t.tv_nsec / 1000000;
 299 }
 300
 301
 302 static uint8_t* odhcp6c_resize_state(enum odhcp6c_state state, ssize_t len)
 303 {
 304         if (len == 0)
 305                 return state_data[state] + state_len[state];
 306
 307         uint8_t *n = realloc(state_data[state], state_len[state] + len);
 308         if (n || state_len[state] + len == 0) {
 309                 state_data[state] = n;
 310                 n += state_len[state];
 311                 state_len[state] += len;
 312         }
 313         return n;
 314 }
 315
 316
 317 bool odhcp6c_signal_is_pending(void)
 318 {
 319         return do_signal != 0;
 320 }
 321
 322
 323 void odhcp6c_clear_state(enum odhcp6c_state state)
 324 {
 325         state_len[state] = 0;
 326 }
 327
 328
 329 void odhcp6c_add_state(enum odhcp6c_state state, const void *data, size_t len)
 330 {
 331         uint8_t *n = odhcp6c_resize_state(state, len);
 332         if (n)
 333                 memcpy(n, data, len);
 334 }
 335
 336
 337 size_t odhcp6c_remove_state(enum odhcp6c_state state, size_t offset, size_t len)
 338 {
 339         uint8_t *data = state_data[state];
 340         ssize_t len_after = state_len[state] - (offset + len);
 341         if (len_after < 0)
 342                 return state_len[state];
 343
 344         memmove(data + offset, data + offset + len, len_after);
 345         return state_len[state] -= len;
 346 }
 347
 348
 349 bool odhcp6c_commit_state(enum odhcp6c_state state, size_t old_len)
 350 {
 351         size_t new_len = state_len[state] - old_len;
 352         uint8_t *old_data = state_data[state], *new_data = old_data + old_len;
 353         bool upd = new_len != old_len || memcmp(old_data, new_data, new_len);
 354
 355         memmove(old_data, new_data, new_len);
 356         odhcp6c_resize_state(state, -old_len);
 357
 358         return upd;
 359 }
 360
 361
 362 void* odhcp6c_get_state(enum odhcp6c_state state, size_t *len)
 363 {
 364         *len = state_len[state];
 365         return state_data[state];
 366 }
 367
 368
 369 static void sighandler(int signal)
 370 {
 371         if (signal == SIGCHLD)
 372                 while (waitpid(-1, NULL, WNOHANG) > 0);
 373         else if (signal == SIGUSR1)
 374                 do_signal = SIGUSR1;
 375         else if (signal == SIGUSR2)
 376                 do_signal = SIGUSR2;
 377         else
 378                 do_signal = SIGTERM;
 379 }