www.tinc-vpn.org Git - tinc/blob - src/net_setup.c

   1 /*
   2     net_setup.c -- Setup.
   3     Copyright (C) 1998-2005 Ivo Timmermans,
   4                   2000-2010 Guus Sliepen <guus@tinc-vpn.org>
   5                   2006      Scott Lamb <slamb@slamb.org>
   6                   2010      Brandon Black <blblack@gmail.com>
   7
   8     This program is free software; you can redistribute it and/or modify
   9     it under the terms of the GNU General Public License as published by
  10     the Free Software Foundation; either version 2 of the License, or
  11     (at your option) any later version.
  12
  13     This program is distributed in the hope that it will be useful,
  14     but WITHOUT ANY WARRANTY; without even the implied warranty of
  15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16     GNU General Public License for more details.
  17
  18     You should have received a copy of the GNU General Public License along
  19     with this program; if not, write to the Free Software Foundation, Inc.,
  20     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21 */
  22
  23 #include "system.h"
  24
  25 #include <openssl/pem.h>
  26 #include <openssl/rsa.h>
  27 #include <openssl/rand.h>
  28 #include <openssl/err.h>
  29 #include <openssl/evp.h>
  30
  31 #include "avl_tree.h"
  32 #include "conf.h"
  33 #include "connection.h"
  34 #include "device.h"
  35 #include "event.h"
  36 #include "graph.h"
  37 #include "logger.h"
  38 #include "net.h"
  39 #include "netutl.h"
  40 #include "process.h"
  41 #include "protocol.h"
  42 #include "route.h"
  43 #include "subnet.h"
  44 #include "utils.h"
  45 #include "xalloc.h"
  46
  47 char *myport;
  48
  49 bool read_rsa_public_key(connection_t *c) {
  50         FILE *fp;
  51         char *fname;
  52         char *key;
  53
  54         if(!c->rsa_key) {
  55                 c->rsa_key = RSA_new();
  56 //              RSA_blinding_on(c->rsa_key, NULL);
  57         }
  58
  59         /* First, check for simple PublicKey statement */
  60
  61         if(get_config_string(lookup_config(c->config_tree, "PublicKey"), &key)) {
  62                 BN_hex2bn(&c->rsa_key->n, key);
  63                 BN_hex2bn(&c->rsa_key->e, "FFFF");
  64                 free(key);
  65                 return true;
  66         }
  67
  68         /* Else, check for PublicKeyFile statement and read it */
  69
  70         if(get_config_string(lookup_config(c->config_tree, "PublicKeyFile"), &fname)) {
  71                 fp = fopen(fname, "r");
  72
  73                 if(!fp) {
  74                         logger(LOG_ERR, "Error reading RSA public key file `%s': %s",
  75                                    fname, strerror(errno));
  76                         free(fname);
  77                         return false;
  78                 }
  79
  80                 free(fname);
  81                 c->rsa_key = PEM_read_RSAPublicKey(fp, &c->rsa_key, NULL, NULL);
  82                 fclose(fp);
  83
  84                 if(c->rsa_key)
  85                         return true;            /* Woohoo. */
  86
  87                 /* If it fails, try PEM_read_RSA_PUBKEY. */
  88                 fp = fopen(fname, "r");
  89
  90                 if(!fp) {
  91                         logger(LOG_ERR, "Error reading RSA public key file `%s': %s",
  92                                    fname, strerror(errno));
  93                         free(fname);
  94                         return false;
  95                 }
  96
  97                 free(fname);
  98                 c->rsa_key = PEM_read_RSA_PUBKEY(fp, &c->rsa_key, NULL, NULL);
  99                 fclose(fp);
 100
 101                 if(c->rsa_key) {
 102 //                              RSA_blinding_on(c->rsa_key, NULL);
 103                         return true;
 104                 }
 105
 106                 logger(LOG_ERR, "Reading RSA public key file `%s' failed: %s",
 107                            fname, strerror(errno));
 108                 return false;
 109         }
 110
 111         /* Else, check if a harnessed public key is in the config file */
 112
 113         xasprintf(&fname, "%s/hosts/%s", confbase, c->name);
 114         fp = fopen(fname, "r");
 115
 116         if(!fp) {
 117                 logger(LOG_ERR, "Error reading RSA public key file `%s': %s", fname, strerror(errno));
 118                 free(fname);
 119                 return false;
 120         }
 121
 122         c->rsa_key = PEM_read_RSAPublicKey(fp, &c->rsa_key, NULL, NULL);
 123         fclose(fp);
 124         free(fname);
 125
 126         if(c->rsa_key)
 127                 return true;
 128
 129         /* Try again with PEM_read_RSA_PUBKEY. */
 130
 131         xasprintf(&fname, "%s/hosts/%s", confbase, c->name);
 132         fp = fopen(fname, "r");
 133
 134         if(!fp) {
 135                 logger(LOG_ERR, "Error reading RSA public key file `%s': %s", fname, strerror(errno));
 136                 free(fname);
 137                 return false;
 138         }
 139
 140         c->rsa_key = PEM_read_RSA_PUBKEY(fp, &c->rsa_key, NULL, NULL);
 141 //      RSA_blinding_on(c->rsa_key, NULL);
 142         fclose(fp);
 143         free(fname);
 144
 145         if(c->rsa_key)
 146                 return true;
 147
 148         logger(LOG_ERR, "No public key for %s specified!", c->name);
 149
 150         return false;
 151 }
 152
 153 static bool read_rsa_private_key(void) {
 154         FILE *fp;
 155         char *fname, *key, *pubkey;
 156         struct stat s;
 157
 158         if(get_config_string(lookup_config(config_tree, "PrivateKey"), &key)) {
 159                 if(!get_config_string(lookup_config(config_tree, "PublicKey"), &pubkey)) {
 160                         logger(LOG_ERR, "PrivateKey used but no PublicKey found!");
 161                         return false;
 162                 }
 163                 myself->connection->rsa_key = RSA_new();
 164 //              RSA_blinding_on(myself->connection->rsa_key, NULL);
 165                 BN_hex2bn(&myself->connection->rsa_key->d, key);
 166                 BN_hex2bn(&myself->connection->rsa_key->n, pubkey);
 167                 BN_hex2bn(&myself->connection->rsa_key->e, "FFFF");
 168                 free(key);
 169                 free(pubkey);
 170                 return true;
 171         }
 172
 173         if(!get_config_string(lookup_config(config_tree, "PrivateKeyFile"), &fname))
 174                 xasprintf(&fname, "%s/rsa_key.priv", confbase);
 175
 176         fp = fopen(fname, "r");
 177
 178         if(!fp) {
 179                 logger(LOG_ERR, "Error reading RSA private key file `%s': %s",
 180                            fname, strerror(errno));
 181                 free(fname);
 182                 return false;
 183         }
 184
 185 #if !defined(HAVE_MINGW) && !defined(HAVE_CYGWIN)
 186         if(fstat(fileno(fp), &s)) {
 187                 logger(LOG_ERR, "Could not stat RSA private key file `%s': %s'",
 188                                 fname, strerror(errno));
 189                 free(fname);
 190                 return false;
 191         }
 192
 193         if(s.st_mode & ~0100700)
 194                 logger(LOG_WARNING, "Warning: insecure file permissions for RSA private key file `%s'!", fname);
 195 #endif
 196
 197         myself->connection->rsa_key = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
 198         fclose(fp);
 199
 200         if(!myself->connection->rsa_key) {
 201                 logger(LOG_ERR, "Reading RSA private key file `%s' failed: %s",
 202                            fname, strerror(errno));
 203                 free(fname);
 204                 return false;
 205         }
 206
 207         free(fname);
 208         return true;
 209 }
 210
 211 /*
 212   Read Subnets from all host config files
 213 */
 214 void load_all_subnets(void) {
 215         DIR *dir;
 216         struct dirent *ent;
 217         char *dname;
 218         char *fname;
 219         avl_tree_t *config_tree;
 220         config_t *cfg;
 221         subnet_t *s, *s2;
 222         node_t *n;
 223         bool result;
 224
 225         xasprintf(&dname, "%s/hosts", confbase);
 226         dir = opendir(dname);
 227         if(!dir) {
 228                 logger(LOG_ERR, "Could not open %s: %s", dname, strerror(errno));
 229                 free(dname);
 230                 return;
 231         }
 232
 233         while((ent = readdir(dir))) {
 234                 if(!check_id(ent->d_name))
 235                         continue;
 236
 237                 n = lookup_node(ent->d_name);
 238                 #ifdef _DIRENT_HAVE_D_TYPE
 239                 //if(ent->d_type != DT_REG)
 240                 //      continue;
 241                 #endif
 242
 243                 xasprintf(&fname, "%s/hosts/%s", confbase, ent->d_name);
 244                 init_configuration(&config_tree);
 245                 result = read_config_file(config_tree, fname);
 246                 free(fname);
 247                 if(!result)
 248                         continue;
 249
 250                 if(!n) {
 251                         n = new_node();
 252                         n->name = xstrdup(ent->d_name);
 253                         node_add(n);
 254                 }
 255
 256                 for(cfg = lookup_config(config_tree, "Subnet"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
 257                         if(!get_config_subnet(cfg, &s))
 258                                 continue;
 259
 260                         if((s2 = lookup_subnet(n, s))) {
 261                                 s2->expires = -1;
 262                         } else {
 263                                 subnet_add(n, s);
 264                         }
 265                 }
 266
 267                 exit_configuration(&config_tree);
 268         }
 269
 270         closedir(dir);
 271 }
 272
 273 /*
 274   Configure node_t myself and set up the local sockets (listen only)
 275 */
 276 static bool setup_myself(void) {
 277         config_t *cfg;
 278         subnet_t *subnet;
 279         char *name, *hostname, *mode, *afname, *cipher, *digest;
 280         char *fname = NULL;
 281         char *address = NULL;
 282         char *envp[5];
 283         struct addrinfo *ai, *aip, hint = {0};
 284         bool choice;
 285         int i, err;
 286         int replaywin_int;
 287
 288         myself = new_node();
 289         myself->connection = new_connection();
 290
 291         myself->hostname = xstrdup("MYSELF");
 292         myself->connection->hostname = xstrdup("MYSELF");
 293
 294         myself->connection->options = 0;
 295         myself->connection->protocol_version = PROT_CURRENT;
 296
 297         if(!get_config_string(lookup_config(config_tree, "Name"), &name)) {     /* Not acceptable */
 298                 logger(LOG_ERR, "Name for tinc daemon required!");
 299                 return false;
 300         }
 301
 302         if(!check_id(name)) {
 303                 logger(LOG_ERR, "Invalid name for myself!");
 304                 free(name);
 305                 return false;
 306         }
 307
 308         myself->name = name;
 309         myself->connection->name = xstrdup(name);
 310         xasprintf(&fname, "%s/hosts/%s", confbase, name);
 311         read_config_options(config_tree, name);
 312         read_config_file(config_tree, fname);
 313         free(fname);
 314
 315         if(!read_rsa_private_key())
 316                 return false;
 317
 318         if(!get_config_string(lookup_config(config_tree, "Port"), &myport))
 319                 myport = xstrdup("655");
 320
 321         if(!atoi(myport)) {
 322                 struct addrinfo *ai = str2addrinfo("localhost", myport, SOCK_DGRAM);
 323                 sockaddr_t sa;
 324                 if(!ai || !ai->ai_addr)
 325                         return false;
 326                 free(myport);
 327                 memcpy(&sa, ai->ai_addr, ai->ai_addrlen);
 328                 sockaddr2str(&sa, NULL, &myport);
 329         }
 330
 331         /* Read in all the subnets specified in the host configuration file */
 332
 333         cfg = lookup_config(config_tree, "Subnet");
 334
 335         while(cfg) {
 336                 if(!get_config_subnet(cfg, &subnet))
 337                         return false;
 338
 339                 subnet_add(myself, subnet);
 340
 341                 cfg = lookup_config_next(config_tree, cfg);
 342         }
 343
 344         /* Check some options */
 345
 346         if(get_config_bool(lookup_config(config_tree, "IndirectData"), &choice) && choice)
 347                 myself->options |= OPTION_INDIRECT;
 348
 349         if(get_config_bool(lookup_config(config_tree, "TCPOnly"), &choice) && choice)
 350                 myself->options |= OPTION_TCPONLY;
 351
 352         if(myself->options & OPTION_TCPONLY)
 353                 myself->options |= OPTION_INDIRECT;
 354
 355         get_config_bool(lookup_config(config_tree, "DirectOnly"), &directonly);
 356         get_config_bool(lookup_config(config_tree, "StrictSubnets"), &strictsubnets);
 357         get_config_bool(lookup_config(config_tree, "TunnelServer"), &tunnelserver);
 358         strictsubnets |= tunnelserver;
 359
 360         if(get_config_string(lookup_config(config_tree, "Mode"), &mode)) {
 361                 if(!strcasecmp(mode, "router"))
 362                         routing_mode = RMODE_ROUTER;
 363                 else if(!strcasecmp(mode, "switch"))
 364                         routing_mode = RMODE_SWITCH;
 365                 else if(!strcasecmp(mode, "hub"))
 366                         routing_mode = RMODE_HUB;
 367                 else {
 368                         logger(LOG_ERR, "Invalid routing mode!");
 369                         return false;
 370                 }
 371                 free(mode);
 372         }
 373
 374         if(get_config_string(lookup_config(config_tree, "Forwarding"), &mode)) {
 375                 if(!strcasecmp(mode, "off"))
 376                         forwarding_mode = FMODE_OFF;
 377                 else if(!strcasecmp(mode, "internal"))
 378                         forwarding_mode = FMODE_INTERNAL;
 379                 else if(!strcasecmp(mode, "kernel"))
 380                         forwarding_mode = FMODE_KERNEL;
 381                 else {
 382                         logger(LOG_ERR, "Invalid forwarding mode!");
 383                         return false;
 384                 }
 385                 free(mode);
 386         }
 387
 388         choice = true;
 389         get_config_bool(lookup_config(config_tree, "PMTUDiscovery"), &choice);
 390         if(choice)
 391                 myself->options |= OPTION_PMTU_DISCOVERY;
 392
 393         choice = true;
 394         get_config_bool(lookup_config(config_tree, "ClampMSS"), &choice);
 395         if(choice)
 396                 myself->options |= OPTION_CLAMP_MSS;
 397
 398         get_config_bool(lookup_config(config_tree, "PriorityInheritance"), &priorityinheritance);
 399
 400 #if !defined(SOL_IP) || !defined(IP_TOS)
 401         if(priorityinheritance)
 402                 logger(LOG_WARNING, "%s not supported on this platform", "PriorityInheritance");
 403 #endif
 404
 405         if(!get_config_int(lookup_config(config_tree, "MACExpire"), &macexpire))
 406                 macexpire = 600;
 407
 408         if(get_config_int(lookup_config(config_tree, "MaxTimeout"), &maxtimeout)) {
 409                 if(maxtimeout <= 0) {
 410                         logger(LOG_ERR, "Bogus maximum timeout!");
 411                         return false;
 412                 }
 413         } else
 414                 maxtimeout = 900;
 415
 416         if(get_config_int(lookup_config(config_tree, "UDPRcvBuf"), &udp_rcvbuf)) {
 417                 if(udp_rcvbuf <= 0) {
 418                         logger(LOG_ERR, "UDPRcvBuf cannot be negative!");
 419                         return false;
 420                 }
 421         }
 422
 423         if(get_config_int(lookup_config(config_tree, "UDPSndBuf"), &udp_sndbuf)) {
 424                 if(udp_sndbuf <= 0) {
 425                         logger(LOG_ERR, "UDPSndBuf cannot be negative!");
 426                         return false;
 427                 }
 428         }
 429
 430         if(get_config_int(lookup_config(config_tree, "ReplayWindow"), &replaywin_int)) {
 431                 if(replaywin_int < 0) {
 432                         logger(LOG_ERR, "ReplayWindow cannot be negative!");
 433                         return false;
 434                 }
 435                 replaywin = (unsigned)replaywin_int;
 436         }
 437
 438         if(get_config_string(lookup_config(config_tree, "AddressFamily"), &afname)) {
 439                 if(!strcasecmp(afname, "IPv4"))
 440                         addressfamily = AF_INET;
 441                 else if(!strcasecmp(afname, "IPv6"))
 442                         addressfamily = AF_INET6;
 443                 else if(!strcasecmp(afname, "any"))
 444                         addressfamily = AF_UNSPEC;
 445                 else {
 446                         logger(LOG_ERR, "Invalid address family!");
 447                         return false;
 448                 }
 449                 free(afname);
 450         }
 451
 452         get_config_bool(lookup_config(config_tree, "Hostnames"), &hostnames);
 453
 454         /* Generate packet encryption key */
 455
 456         if(get_config_string
 457            (lookup_config(config_tree, "Cipher"), &cipher)) {
 458                 if(!strcasecmp(cipher, "none")) {
 459                         myself->incipher = NULL;
 460                 } else {
 461                         myself->incipher = EVP_get_cipherbyname(cipher);
 462
 463                         if(!myself->incipher) {
 464                                 logger(LOG_ERR, "Unrecognized cipher type!");
 465                                 return false;
 466                         }
 467                 }
 468         } else
 469                 myself->incipher = EVP_bf_cbc();
 470
 471         if(myself->incipher)
 472                 myself->inkeylength = myself->incipher->key_len + myself->incipher->iv_len;
 473         else
 474                 myself->inkeylength = 1;
 475
 476         myself->connection->outcipher = EVP_bf_ofb();
 477
 478         if(!get_config_int(lookup_config(config_tree, "KeyExpire"), &keylifetime))
 479                 keylifetime = 3600;
 480
 481         keyexpires = now + keylifetime;
 482
 483         /* Check if we want to use message authentication codes... */
 484
 485         if(get_config_string(lookup_config(config_tree, "Digest"), &digest)) {
 486                 if(!strcasecmp(digest, "none")) {
 487                         myself->indigest = NULL;
 488                 } else {
 489                         myself->indigest = EVP_get_digestbyname(digest);
 490
 491                         if(!myself->indigest) {
 492                                 logger(LOG_ERR, "Unrecognized digest type!");
 493                                 return false;
 494                         }
 495                 }
 496         } else
 497                 myself->indigest = EVP_sha1();
 498
 499         myself->connection->outdigest = EVP_sha1();
 500
 501         if(get_config_int(lookup_config(config_tree, "MACLength"), &myself->inmaclength)) {
 502                 if(myself->indigest) {
 503                         if(myself->inmaclength > myself->indigest->md_size) {
 504                                 logger(LOG_ERR, "MAC length exceeds size of digest!");
 505                                 return false;
 506                         } else if(myself->inmaclength < 0) {
 507                                 logger(LOG_ERR, "Bogus MAC length!");
 508                                 return false;
 509                         }
 510                 }
 511         } else
 512                 myself->inmaclength = 4;
 513
 514         myself->connection->outmaclength = 0;
 515
 516         /* Compression */
 517
 518         if(get_config_int(lookup_config(config_tree, "Compression"), &myself->incompression)) {
 519                 if(myself->incompression < 0 || myself->incompression > 11) {
 520                         logger(LOG_ERR, "Bogus compression level!");
 521                         return false;
 522                 }
 523         } else
 524                 myself->incompression = 0;
 525
 526         myself->connection->outcompression = 0;
 527
 528         /* Done */
 529
 530         myself->nexthop = myself;
 531         myself->via = myself;
 532         myself->status.reachable = true;
 533         node_add(myself);
 534
 535         graph();
 536
 537         if(strictsubnets)
 538                 load_all_subnets();
 539
 540         /* Open device */
 541
 542         if(!setup_device())
 543                 return false;
 544
 545         /* Run tinc-up script to further initialize the tap interface */
 546         xasprintf(&envp[0], "NETNAME=%s", netname ? : "");
 547         xasprintf(&envp[1], "DEVICE=%s", device ? : "");
 548         xasprintf(&envp[2], "INTERFACE=%s", iface ? : "");
 549         xasprintf(&envp[3], "NAME=%s", myself->name);
 550         envp[4] = NULL;
 551
 552         execute_script("tinc-up", envp);
 553
 554         for(i = 0; i < 5; i++)
 555                 free(envp[i]);
 556
 557         /* Run subnet-up scripts for our own subnets */
 558
 559         subnet_update(myself, NULL, true);
 560
 561         /* Open sockets */
 562
 563         get_config_string(lookup_config(config_tree, "BindToAddress"), &address);
 564
 565         hint.ai_family = addressfamily;
 566         hint.ai_socktype = SOCK_STREAM;
 567         hint.ai_protocol = IPPROTO_TCP;
 568         hint.ai_flags = AI_PASSIVE;
 569
 570         err = getaddrinfo(address, myport, &hint, &ai);
 571
 572         if(err || !ai) {
 573                 logger(LOG_ERR, "System call `%s' failed: %s", "getaddrinfo",
 574                            gai_strerror(err));
 575                 return false;
 576         }
 577
 578         listen_sockets = 0;
 579
 580         for(aip = ai; aip; aip = aip->ai_next) {
 581                 listen_socket[listen_sockets].tcp =
 582                         setup_listen_socket((sockaddr_t *) aip->ai_addr);
 583
 584                 if(listen_socket[listen_sockets].tcp < 0)
 585                         continue;
 586
 587                 listen_socket[listen_sockets].udp =
 588                         setup_vpn_in_socket((sockaddr_t *) aip->ai_addr);
 589
 590                 if(listen_socket[listen_sockets].udp < 0)
 591                         continue;
 592
 593                 ifdebug(CONNECTIONS) {
 594                         hostname = sockaddr2hostname((sockaddr_t *) aip->ai_addr);
 595                         logger(LOG_NOTICE, "Listening on %s", hostname);
 596                         free(hostname);
 597                 }
 598
 599                 memcpy(&listen_socket[listen_sockets].sa, aip->ai_addr, aip->ai_addrlen);
 600                 listen_sockets++;
 601         }
 602
 603         freeaddrinfo(ai);
 604
 605         if(listen_sockets)
 606                 logger(LOG_NOTICE, "Ready");
 607         else {
 608                 logger(LOG_ERR, "Unable to create any listening socket!");
 609                 return false;
 610         }
 611
 612         return true;
 613 }
 614
 615 /*
 616   initialize network
 617 */
 618 bool setup_network(void) {
 619         now = time(NULL);
 620
 621         init_events();
 622         init_connections();
 623         init_subnets();
 624         init_nodes();
 625         init_edges();
 626         init_requests();
 627
 628         if(get_config_int(lookup_config(config_tree, "PingInterval"), &pinginterval)) {
 629                 if(pinginterval < 1) {
 630                         pinginterval = 86400;
 631                 }
 632         } else
 633                 pinginterval = 60;
 634
 635         if(!get_config_int(lookup_config(config_tree, "PingTimeout"), &pingtimeout))
 636                 pingtimeout = 5;
 637         if(pingtimeout < 1 || pingtimeout > pinginterval)
 638                 pingtimeout = pinginterval;
 639
 640         if(!get_config_int(lookup_config(config_tree, "MaxOutputBufferSize"), &maxoutbufsize))
 641                 maxoutbufsize = 10 * MTU;
 642
 643         if(!setup_myself())
 644                 return false;
 645
 646         return true;
 647 }
 648
 649 /*
 650   close all open network connections
 651 */
 652 void close_network_connections(void) {
 653         avl_node_t *node, *next;
 654         connection_t *c;
 655         char *envp[5];
 656         int i;
 657
 658         for(node = connection_tree->head; node; node = next) {
 659                 next = node->next;
 660                 c = node->data;
 661                 c->outgoing = NULL;
 662                 terminate_connection(c, false);
 663         }
 664
 665         for(list_node_t *node = outgoing_list->head; node; node = node->next) {
 666                 outgoing_t *outgoing = node->data;
 667
 668                 if(outgoing->event)
 669                         event_del(outgoing->event);
 670         }
 671
 672         list_delete_list(outgoing_list);
 673
 674         if(myself && myself->connection) {
 675                 subnet_update(myself, NULL, false);
 676                 terminate_connection(myself->connection, false);
 677                 free_connection(myself->connection);
 678         }
 679
 680         for(i = 0; i < listen_sockets; i++) {
 681                 close(listen_socket[i].tcp);
 682                 close(listen_socket[i].udp);
 683         }
 684
 685         xasprintf(&envp[0], "NETNAME=%s", netname ? : "");
 686         xasprintf(&envp[1], "DEVICE=%s", device ? : "");
 687         xasprintf(&envp[2], "INTERFACE=%s", iface ? : "");
 688         xasprintf(&envp[3], "NAME=%s", myself->name);
 689         envp[4] = NULL;
 690
 691         exit_requests();
 692         exit_edges();
 693         exit_subnets();
 694         exit_nodes();
 695         exit_connections();
 696         exit_events();
 697
 698         execute_script("tinc-down", envp);
 699
 700         if(myport) free(myport);
 701
 702         for(i = 0; i < 4; i++)
 703                 free(envp[i]);
 704
 705         close_device();
 706
 707         return;
 708 }