curvetun.c

   1 /*
   2  * curvetun - the cipherspace wormhole creator
   3  * Part of the netsniff-ng project
   4  * Copyright 2011 Daniel Borkmann <dborkma@tik.ee.ethz.ch>,
   5  * Copyright 2011 Emmanuel Roullit.
   6  * Subject to the GPL, version 2.
   7  *
   8  *   He used often to say there was only one Road; that it was like a great
   9  *   river: it's springs were at every doorstep and every path was it's
  10  *   tributary. "It's a dangerous business, Frodo, going out of your door,"
  11  *   he used to say. "You step into the Road, and if you don't keep your
  12  *   feet, there is no telling where you might be swept off to."
  13  *
  14  *     -- The Lord of the Rings, Frodo about his uncle Bilbo Baggins,
  15  *        Chapter 'Three is Company'.
  16  */
  17
  18 #define _GNU_SOURCE
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <fcntl.h>
  22 #include <string.h>
  23 #include <ctype.h>
  24 #include <getopt.h>
  25 #include <errno.h>
  26 #include <stdbool.h>
  27 #include <limits.h>
  28 #include <sys/types.h>
  29 #include <sys/stat.h>
  30 #include <sys/socket.h>
  31 #include <sys/ptrace.h>
  32 #include <sys/fsuid.h>
  33 #include <netinet/in.h>
  34 #include <unistd.h>
  35 #include <signal.h>
  36
  37 #include "xutils.h"
  38 #include "die.h"
  39 #include "xmalloc.h"
  40 #include "curvetun.h"
  41 #include "curve.h"
  42 #include "ct_usermgmt.h"
  43 #include "ct_servmgmt.h"
  44 #include "xio.h"
  45 #include "tprintf.h"
  46 #include "crypto_verify_32.h"
  47 #include "crypto_box_curve25519xsalsa20poly1305.h"
  48 #include "crypto_scalarmult_curve25519.h"
  49 #include "crypto_auth_hmacsha512256.h"
  50
  51 #define CURVETUN_ENTROPY_SOURCE "/dev/random"
  52
  53 extern void print_stun_probe(char *server, uint16_t sport, uint16_t tunport);
  54
  55 enum working_mode {
  56         MODE_UNKNOW,
  57         MODE_KEYGEN,
  58         MODE_EXPORT,
  59         MODE_DUMPC,
  60         MODE_DUMPS,
  61         MODE_CLIENT,
  62         MODE_SERVER,
  63 };
  64
  65 volatile sig_atomic_t sigint = 0;
  66
  67 static const char *short_options = "kxc::svhp:t:d:uCS46DN";
  68 static const struct option long_options[] = {
  69         {"client",      optional_argument,      NULL, 'c'},
  70         {"dev",         required_argument,      NULL, 'd'},
  71         {"port",        required_argument,      NULL, 'p'},
  72         {"stun",        required_argument,      NULL, 't'},
  73         {"keygen",      no_argument,            NULL, 'k'},
  74         {"export",      no_argument,            NULL, 'x'},
  75         {"dumpc",       no_argument,            NULL, 'C'},
  76         {"dumps",       no_argument,            NULL, 'S'},
  77         {"no-logging",  no_argument,            NULL, 'N'},
  78         {"server",      no_argument,            NULL, 's'},
  79         {"udp",         no_argument,            NULL, 'u'},
  80         {"ipv4",        no_argument,            NULL, '4'},
  81         {"ipv6",        no_argument,            NULL, '6'},
  82         {"nofork",      no_argument,            NULL, 'D'},
  83         {"version",     no_argument,            NULL, 'v'},
  84         {"help",        no_argument,            NULL, 'h'},
  85         {NULL, 0, NULL, 0}
  86 };
  87
  88 static void signal_handler(int number)
  89 {
  90         switch (number) {
  91         case SIGINT:
  92                 sigint = 1;
  93                 break;
  94         default:
  95                 break;
  96         }
  97 }
  98
  99 static void help(void)
 100 {
 101         printf("\ncurvetun %s, lightweight curve25519-based VPN/IP tunnel\n", VERSION_STRING);
 102         puts("http://www.netsniff-ng.org\n\n"
 103              "Usage: curvetun [options]\n"
 104              "Options, general:\n"
 105              "  -d|--dev <tun>          Networking tunnel device, e.g. tun0\n"
 106              "  -p|--port <num>         Server port number (mandatory)\n"
 107              "  -t|--stun <server>      Show public IP/Port mapping via STUN\n"
 108              "  -c|--client[=alias]     Client mode, server alias optional\n"
 109              "  -k|--keygen             Generate public/private keypair\n"
 110              "  -x|--export             Export your public data for remote servers\n"
 111              "  -C|--dumpc              Dump parsed clients\n"
 112              "  -S|--dumps              Dump parsed servers\n"
 113              "  -D|--nofork             Do not daemonize\n"
 114              "  -s|--server             Server mode, options follow below\n"
 115              "  -N|--no-logging         Disable server logging (for better anonymity)\n"
 116              "  -u|--udp                Use UDP as carrier instead of TCP\n"
 117              "  -4|--ipv4               Tunnel devices are IPv4\n"
 118              "  -6|--ipv6               Tunnel devices are IPv6\n"
 119              "  -v|--version            Print version\n"
 120              "  -h|--help               Print this help\n\n"
 121              "Example:\n"
 122              "  See Documentation/Curvetun for a configuration example.\n"
 123              "  curvetun --server -4 -u -N --port 6666 --stun stunserver.org\n"
 124              "  curvetun --client=ethz\n\n"
 125              "  curvetun --keygen\n"
 126              "  curvetun --export\n"
 127              "Note:\n"
 128              "  There is no default port specified, so that you are forced\n"
 129              "  to select your own! For client/server status messages see syslog!\n"
 130              "  This software is an experimental prototype intended for researchers.\n\n"
 131              "Secret ingredient: 7647-14-5\n\n"
 132              "Please report bugs to <bugs@netsniff-ng.org>\n"
 133              "Copyright (C) 2011-2013 Daniel Borkmann <dborkma@tik.ee.ethz.ch>,\n"
 134              "Swiss federal institute of technology (ETH Zurich)\n"
 135              "License: GNU GPL version 2.0\n"
 136              "This is free software: you are free to change and redistribute it.\n"
 137              "There is NO WARRANTY, to the extent permitted by law.\n");
 138         die();
 139 }
 140
 141 static void version(void)
 142 {
 143         printf("\ncurvetun %s, lightweight curve25519-based VPN/IP tunnel\n", VERSION_STRING);
 144         puts("http://www.netsniff-ng.org\n\n"
 145              "Please report bugs to <bugs@netsniff-ng.org>\n"
 146              "Copyright (C) 2011-2013 Daniel Borkmann <dborkma@tik.ee.ethz.ch>,\n"
 147              "Swiss federal institute of technology (ETH Zurich)\n"
 148              "License: GNU GPL version 2.0\n"
 149              "This is free software: you are free to change and redistribute it.\n"
 150              "There is NO WARRANTY, to the extent permitted by law.\n");
 151         die();
 152 }
 153
 154 static void check_file_or_die(char *home, char *file, int maybeempty)
 155 {
 156         char path[PATH_MAX];
 157         struct stat st;
 158
 159         memset(path, 0, sizeof(path));
 160         slprintf(path, sizeof(path), "%s/%s", home, file);
 161
 162         if (stat(path, &st))
 163                 panic("No such file %s! Type --help for further information\n",
 164                       path);
 165
 166         if (!S_ISREG(st.st_mode))
 167                 panic("%s is not a regular file!\n", path);
 168
 169         if ((st.st_mode & ~S_IFREG) != (S_IRUSR | S_IWUSR))
 170                 panic("You have set too many permissions on %s (%o)!\n",
 171                       path, st.st_mode);
 172
 173         if (maybeempty == 0 && st.st_size == 0)
 174                 panic("%s is empty!\n", path);
 175 }
 176
 177 static void check_config_exists_or_die(char *home)
 178 {
 179         if (!home)
 180                 panic("No home dir specified!\n");
 181
 182         check_file_or_die(home, FILE_CLIENTS, 1);
 183         check_file_or_die(home, FILE_SERVERS, 1);
 184         check_file_or_die(home, FILE_PRIVKEY, 0);
 185         check_file_or_die(home, FILE_PUBKEY, 0);
 186         check_file_or_die(home, FILE_USERNAM, 0);
 187 }
 188
 189 static char *fetch_home_dir(void)
 190 {
 191         char *home = getenv("HOME");
 192         if (!home)
 193                 panic("No HOME defined!\n");
 194         return home;
 195 }
 196
 197 static void write_username(char *home)
 198 {
 199         int fd, ret;
 200         char path[PATH_MAX];
 201         char user[512];
 202
 203         memset(path, 0, sizeof(path));
 204         slprintf(path, sizeof(path), "%s/%s", home, FILE_USERNAM);
 205
 206         printf("Username: [%s] ", getenv("USER"));
 207         fflush(stdout);
 208
 209         memset(user, 0, sizeof(user));
 210         if (fgets(user, sizeof(user), stdin) == NULL)
 211                 panic("Could not read from stdin!\n");
 212         user[sizeof(user) - 1] = 0;
 213         user[strlen(user) - 1] = 0; /* omit last \n */
 214         if (strlen(user) == 0)
 215                 strlcpy(user, getenv("USER"), sizeof(user));
 216
 217         fd = open_or_die_m(path, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
 218
 219         ret = write(fd, user, strlen(user));
 220         if (ret != strlen(user))
 221                 panic("Could not write username!\n");
 222
 223         close(fd);
 224
 225         printf("Username written to %s!\n", path);
 226 }
 227
 228 static void create_curvedir(char *home)
 229 {
 230         int ret;
 231         char path[PATH_MAX];
 232
 233         memset(path, 0, sizeof(path));
 234         slprintf(path, sizeof(path), "%s/%s", home, ".curvetun/");
 235
 236         errno = 0;
 237
 238         ret = mkdir(path, S_IRWXU);
 239         if (ret < 0 && errno != EEXIST)
 240                 panic("Cannot create curvetun dir!\n");
 241
 242         printf("curvetun directory %s created!\n", path);
 243         /* We also create empty files for clients and servers! */
 244
 245         memset(path, 0, sizeof(path));
 246         slprintf(path, sizeof(path), "%s/%s", home, FILE_CLIENTS);
 247
 248         create_or_die(path, S_IRUSR | S_IWUSR);
 249
 250         printf("Empty client file written to %s!\n", path);
 251
 252         memset(path, 0, sizeof(path));
 253         slprintf(path, sizeof(path), "%s/%s", home, FILE_SERVERS);
 254
 255         create_or_die(path, S_IRUSR | S_IWUSR);
 256
 257         printf("Empty server file written to %s!\n", path);
 258 }
 259
 260 static void create_keypair(char *home)
 261 {
 262         int fd, err = 0;
 263         ssize_t ret;
 264         unsigned char publickey[crypto_box_curve25519xsalsa20poly1305_PUBLICKEYBYTES] = { 0 };
 265         unsigned char secretkey[crypto_box_curve25519xsalsa20poly1305_SECRETKEYBYTES] = { 0 };
 266         char path[PATH_MAX];
 267         const char * errstr = NULL;
 268
 269         printf("Reading from %s (this may take a while) ...\n", CURVETUN_ENTROPY_SOURCE);
 270
 271         fd = open_or_die(CURVETUN_ENTROPY_SOURCE, O_RDONLY);
 272
 273         ret = read_exact(fd, secretkey, sizeof(secretkey), 0);
 274         if (ret != sizeof(secretkey)) {
 275                 err = EIO;
 276                 errstr = "Cannot read from "CURVETUN_ENTROPY_SOURCE"!\n";
 277                 goto out;
 278         }
 279
 280         close(fd);
 281
 282         crypto_scalarmult_curve25519_base(publickey, secretkey);
 283
 284         memset(path, 0, sizeof(path));
 285         slprintf(path, sizeof(path), "%s/%s", home, FILE_PUBKEY);
 286
 287         fd = open(path, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
 288         if (fd < 0) {
 289                 err = EIO;
 290                 errstr = "Cannot open pubkey file!\n";
 291                 goto out;
 292         }
 293
 294         ret = write(fd, publickey, sizeof(publickey));
 295         if (ret != sizeof(publickey)) {
 296                 err = EIO;
 297                 errstr = "Cannot write public key!\n";
 298                 goto out;
 299         }
 300
 301         close(fd);
 302
 303         printf("Public key written to %s!\n", path);
 304
 305         memset(path, 0, sizeof(path));
 306         slprintf(path, sizeof(path), "%s/%s", home, FILE_PRIVKEY);
 307
 308         fd = open(path, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
 309         if (fd < 0) {
 310                 err = EIO;
 311                 errstr = "Cannot open privkey file!\n";
 312                 goto out;
 313         }
 314
 315         ret = write(fd, secretkey, sizeof(secretkey));
 316         if (ret != sizeof(secretkey)) {
 317                 err = EIO;
 318                 errstr = "Cannot write private key!\n";
 319                 goto out;
 320         }
 321 out:
 322         close(fd);
 323
 324         xmemset(publickey, 0, sizeof(publickey));
 325         xmemset(secretkey, 0, sizeof(secretkey));
 326
 327         if (err)
 328                 panic("%s: %s", errstr, strerror(errno));
 329         else
 330                 printf("Private key written to %s!\n", path);
 331 }
 332
 333 static void check_config_keypair_or_die(char *home)
 334 {
 335         int fd, err;
 336         ssize_t ret;
 337         const char * errstr = NULL;
 338         unsigned char publickey[crypto_box_curve25519xsalsa20poly1305_PUBLICKEYBYTES];
 339         unsigned char publicres[crypto_box_curve25519xsalsa20poly1305_PUBLICKEYBYTES];
 340         unsigned char secretkey[crypto_box_curve25519xsalsa20poly1305_SECRETKEYBYTES];
 341         char path[PATH_MAX];
 342
 343         memset(path, 0, sizeof(path));
 344         slprintf(path, sizeof(path), "%s/%s", home, FILE_PRIVKEY);
 345
 346         fd = open(path, O_RDONLY);
 347         if (fd < 0) {
 348                 err = EIO;
 349                 errstr = "Cannot open privkey file!\n";
 350                 goto out;
 351         }
 352
 353         ret = read(fd, secretkey, sizeof(secretkey));
 354         if (ret != sizeof(secretkey)) {
 355                 err = EIO;
 356                 errstr = "Cannot read private key!\n";
 357                 goto out;
 358         }
 359
 360         close(fd);
 361
 362         memset(path, 0, sizeof(path));
 363         slprintf(path, sizeof(path), "%s/%s", home, FILE_PUBKEY);
 364
 365         fd = open(path, O_RDONLY);
 366         if (fd < 0) {
 367                 err = EIO;
 368                 errstr = "Cannot open pubkey file!\n";
 369                 goto out;
 370         }
 371
 372         ret = read(fd, publickey, sizeof(publickey));
 373         if (ret != sizeof(publickey)) {
 374                 err = EIO;
 375                 errstr = "Cannot read public key!\n";
 376                 goto out;
 377         }
 378
 379         crypto_scalarmult_curve25519_base(publicres, secretkey);
 380
 381         err = crypto_verify_32(publicres, publickey);
 382         if (err) {
 383                 err = EINVAL;
 384                 errstr = "WARNING: your keypair is corrupted!!! You need to "
 385                          "generate new keys!!!\n";
 386                 goto out;
 387         }
 388 out:
 389         close(fd);
 390
 391         xmemset(publickey, 0, sizeof(publickey));
 392         xmemset(publicres, 0, sizeof(publicres));
 393         xmemset(secretkey, 0, sizeof(secretkey));
 394
 395         if (err)
 396                 panic("%s: %s\n", errstr, strerror(errno));
 397 }
 398
 399 static int main_keygen(char *home)
 400 {
 401         create_curvedir(home);
 402         write_username(home);
 403         create_keypair(home);
 404         check_config_keypair_or_die(home);
 405
 406         return 0;
 407 }
 408
 409 static int main_export(char *home)
 410 {
 411         int fd, i;
 412         ssize_t ret;
 413         char path[PATH_MAX], tmp[64];
 414
 415         check_config_exists_or_die(home);
 416         check_config_keypair_or_die(home);
 417
 418         printf("Your exported public information:\n\n");
 419
 420         memset(path, 0, sizeof(path));
 421         slprintf(path, sizeof(path), "%s/%s", home, FILE_USERNAM);
 422
 423         fd = open_or_die(path, O_RDONLY);
 424
 425         while ((ret = read(fd, tmp, sizeof(tmp))) > 0) {
 426                 ret = write(STDOUT_FILENO, tmp, ret);
 427         }
 428
 429         close(fd);
 430
 431         printf(";");
 432
 433         memset(path, 0, sizeof(path));
 434         slprintf(path, sizeof(path), "%s/%s", home, FILE_PUBKEY);
 435
 436         fd = open_or_die(path, O_RDONLY);
 437
 438         ret = read(fd, tmp, sizeof(tmp));
 439         if (ret != crypto_box_curve25519xsalsa20poly1305_PUBLICKEYBYTES)
 440                 panic("Cannot read public key!\n");
 441
 442         for (i = 0; i < ret; ++i)
 443                 if (i == ret - 1)
 444                         printf("%02x\n\n", (unsigned char) tmp[i]);
 445                 else
 446                         printf("%02x:", (unsigned char) tmp[i]);
 447
 448         close(fd);
 449         fflush(stdout);
 450
 451         return 0;
 452 }
 453
 454 static int main_dumpc(char *home)
 455 {
 456         check_config_exists_or_die(home);
 457         check_config_keypair_or_die(home);
 458
 459         printf("Your clients:\n\n");
 460
 461         parse_userfile_and_generate_user_store_or_die(home);
 462
 463         dump_user_store();
 464
 465         destroy_user_store();
 466
 467         printf("\n");
 468         die();
 469         return 0;
 470 }
 471
 472 static int main_dumps(char *home)
 473 {
 474         check_config_exists_or_die(home);
 475         check_config_keypair_or_die(home);
 476
 477         printf("Your servers:\n\n");
 478
 479         parse_userfile_and_generate_serv_store_or_die(home);
 480
 481         dump_serv_store();
 482
 483         destroy_serv_store();
 484
 485         printf("\n");
 486         die();
 487         return 0;
 488 }
 489
 490 static void daemonize(const char *lockfile)
 491 {
 492         char pidstr[8];
 493         mode_t lperm = S_IRWXU | S_IRGRP | S_IXGRP; /* 0750 */
 494         int lfp;
 495
 496         if (getppid() == 1)
 497                 return;
 498
 499         if (daemon(0, 1))
 500                 panic("Cannot daemonize: %s", strerror(errno));
 501
 502         to_std_log(&stdout);
 503         to_std_log(&stderr);
 504
 505         umask(lperm);
 506         if (lockfile) {
 507                 lfp = open(lockfile, O_RDWR | O_CREAT | O_EXCL,
 508                            S_IRUSR | S_IWUSR | S_IRGRP);
 509                 if (lfp < 0)
 510                         syslog_panic("Cannot create lockfile at %s! "
 511                                      "curvetun server already running?\n",
 512                                      lockfile);
 513
 514                 slprintf(pidstr, sizeof(pidstr), "%u", getpid());
 515                 if (write(lfp, pidstr, strlen(pidstr)) <= 0)
 516                         syslog_panic("Could not write pid to pidfile %s",
 517                                      lockfile);
 518
 519                 close(lfp);
 520         }
 521 }
 522
 523 static int main_client(char *home, char *dev, char *alias, int daemon)
 524 {
 525         int ret, udp;
 526         char *host, *port;
 527
 528         check_config_exists_or_die(home);
 529         check_config_keypair_or_die(home);
 530
 531         parse_userfile_and_generate_serv_store_or_die(home);
 532
 533         get_serv_store_entry_by_alias(alias, alias ? strlen(alias) + 1 : 0,
 534                                       &host, &port, &udp);
 535         if (!host || !port || udp < 0)
 536                 panic("Did not find alias/entry in configuration!\n");
 537
 538         printf("Using [%s] -> %s:%s via %s as endpoint!\n",
 539                alias ? : "default", host, port, udp ? "udp" : "tcp");
 540         if (daemon)
 541                 daemonize(NULL);
 542
 543         ret = client_main(home, dev, host, port, udp);
 544
 545         destroy_serv_store();
 546
 547         return ret;
 548 }
 549
 550 static int main_server(char *home, char *dev, char *port, int udp,
 551                        int ipv4, int daemon, int log)
 552 {
 553         int ret;
 554
 555         check_config_exists_or_die(home);
 556         check_config_keypair_or_die(home);
 557
 558         if (daemon)
 559                 daemonize(LOCKFILE);
 560
 561         ret = server_main(home, dev, port, udp, ipv4, log);
 562
 563         unlink(LOCKFILE);
 564
 565         return ret;
 566 }
 567
 568 int main(int argc, char **argv)
 569 {
 570         int ret = 0, c, opt_index, udp = 0, ipv4 = -1, daemon = 1, log = 1;
 571         char *port = NULL, *stun = NULL, *dev = NULL, *home = NULL, *alias = NULL;
 572         enum working_mode wmode = MODE_UNKNOW;
 573
 574         setfsuid(getuid());
 575         setfsgid(getgid());
 576
 577         home = fetch_home_dir();
 578
 579         while ((c = getopt_long(argc, argv, short_options, long_options,
 580                &opt_index)) != EOF) {
 581                 switch (c) {
 582                 case 'h':
 583                         help();
 584                         break;
 585                 case 'v':
 586                         version();
 587                         break;
 588                 case 'D':
 589                         daemon = 0;
 590                         break;
 591                 case 'N':
 592                         log = 0;
 593                         break;
 594                 case 'C':
 595                         wmode = MODE_DUMPC;
 596                         break;
 597                 case 'S':
 598                         wmode = MODE_DUMPS;
 599                         break;
 600                 case 'c':
 601                         wmode = MODE_CLIENT;
 602                         if (optarg) {
 603                                 if (*optarg == '=')
 604                                         optarg++;
 605                                 alias = xstrdup(optarg);
 606                         }
 607                         break;
 608                 case 'd':
 609                         dev = xstrdup(optarg);
 610                         break;
 611                 case 'k':
 612                         wmode = MODE_KEYGEN;
 613                         break;
 614                 case '4':
 615                         ipv4 = 1;
 616                         break;
 617                 case '6':
 618                         ipv4 = 0;
 619                         break;
 620                 case 'x':
 621                         wmode = MODE_EXPORT;
 622                         break;
 623                 case 's':
 624                         wmode = MODE_SERVER;
 625                         break;
 626                 case 'u':
 627                         udp = 1;
 628                         break;
 629                 case 't':
 630                         stun = xstrdup(optarg);
 631                         break;
 632                 case 'p':
 633                         port = xstrdup(optarg);
 634                         break;
 635                 case '?':
 636                         switch (optopt) {
 637                         case 't':
 638                         case 'd':
 639                         case 'u':
 640                         case 'p':
 641                                 panic("Option -%c requires an argument!\n",
 642                                       optopt);
 643                         default:
 644                                 if (isprint(optopt))
 645                                         printf("Unknown option character `0x%X\'!\n", optopt);
 646                                 die();
 647                         }
 648                 default:
 649                         break;
 650                 }
 651         }
 652
 653         if (argc < 2)
 654                 help();
 655
 656         register_signal(SIGINT, signal_handler);
 657         register_signal(SIGHUP, signal_handler);
 658         register_signal(SIGTERM, signal_handler);
 659         register_signal(SIGPIPE, signal_handler);
 660
 661         curve25519_selftest();
 662
 663         switch (wmode) {
 664         case MODE_KEYGEN:
 665                 ret = main_keygen(home);
 666                 break;
 667         case MODE_EXPORT:
 668                 ret = main_export(home);
 669                 break;
 670         case MODE_DUMPC:
 671                 ret = main_dumpc(home);
 672                 break;
 673         case MODE_DUMPS:
 674                 ret = main_dumps(home);
 675                 break;
 676         case MODE_CLIENT:
 677                 ret = main_client(home, dev, alias, daemon);
 678                 break;
 679         case MODE_SERVER:
 680                 if (!port)
 681                         panic("No port specified!\n");
 682                 if (stun)
 683                         print_stun_probe(stun, 3478, strtoul(port, NULL, 10));
 684                 ret = main_server(home, dev, port, udp, ipv4, daemon, log);
 685                 break;
 686         default:
 687                 die();
 688         }
 689
 690         if (dev)
 691                 xfree(dev);
 692         if (stun)
 693                 xfree(stun);
 694         if (port)
 695                 xfree(port);
 696         if (alias)
 697                 xfree(alias);
 698
 699         return ret;
 700 }