misc.c

   1 /* $OpenBSD: misc.c,v 1.74 2009/12/25 19:40:21 stevesk Exp $ */
   2 /*
   3  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
   4  * Copyright (c) 2005,2006 Damien Miller.  All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include "includes.h"
  28
  29 #include <sys/types.h>
  30 #include <sys/ioctl.h>
  31 #include <sys/socket.h>
  32 #include <sys/param.h>
  33
  34 #include <stdarg.h>
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38 #include <unistd.h>
  39
  40 #include <netinet/in.h>
  41 #include <netinet/tcp.h>
  42
  43 #include <errno.h>
  44 #include <fcntl.h>
  45 #include <netdb.h>
  46 #ifdef HAVE_PATHS_H
  47 # include <paths.h>
  48 #include <pwd.h>
  49 #endif
  50 #ifdef SSH_TUN_OPENBSD
  51 #include <net/if.h>
  52 #endif
  53
  54 #include "xmalloc.h"
  55 #include "misc.h"
  56 #include "log.h"
  57 #include "ssh.h"
  58
  59 /* remove newline at end of string */
  60 char *
  61 chop(char *s)
  62 {
  63         char *t = s;
  64         while (*t) {
  65                 if (*t == '\n' || *t == '\r') {
  66                         *t = '\0';
  67                         return s;
  68                 }
  69                 t++;
  70         }
  71         return s;
  72
  73 }
  74
  75 /* set/unset filedescriptor to non-blocking */
  76 int
  77 set_nonblock(int fd)
  78 {
  79         int val;
  80
  81         val = fcntl(fd, F_GETFL, 0);
  82         if (val < 0) {
  83                 error("fcntl(%d, F_GETFL, 0): %s", fd, strerror(errno));
  84                 return (-1);
  85         }
  86         if (val & O_NONBLOCK) {
  87                 debug3("fd %d is O_NONBLOCK", fd);
  88                 return (0);
  89         }
  90         debug2("fd %d setting O_NONBLOCK", fd);
  91         val |= O_NONBLOCK;
  92         if (fcntl(fd, F_SETFL, val) == -1) {
  93                 debug("fcntl(%d, F_SETFL, O_NONBLOCK): %s", fd,
  94                     strerror(errno));
  95                 return (-1);
  96         }
  97         return (0);
  98 }
  99
 100 int
 101 unset_nonblock(int fd)
 102 {
 103         int val;
 104
 105         val = fcntl(fd, F_GETFL, 0);
 106         if (val < 0) {
 107                 error("fcntl(%d, F_GETFL, 0): %s", fd, strerror(errno));
 108                 return (-1);
 109         }
 110         if (!(val & O_NONBLOCK)) {
 111                 debug3("fd %d is not O_NONBLOCK", fd);
 112                 return (0);
 113         }
 114         debug("fd %d clearing O_NONBLOCK", fd);
 115         val &= ~O_NONBLOCK;
 116         if (fcntl(fd, F_SETFL, val) == -1) {
 117                 debug("fcntl(%d, F_SETFL, ~O_NONBLOCK): %s",
 118                     fd, strerror(errno));
 119                 return (-1);
 120         }
 121         return (0);
 122 }
 123
 124 const char *
 125 ssh_gai_strerror(int gaierr)
 126 {
 127         if (gaierr == EAI_SYSTEM)
 128                 return strerror(errno);
 129         return gai_strerror(gaierr);
 130 }
 131
 132 /* disable nagle on socket */
 133 void
 134 set_nodelay(int fd)
 135 {
 136         int opt;
 137         socklen_t optlen;
 138
 139         optlen = sizeof opt;
 140         if (getsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, &optlen) == -1) {
 141                 debug("getsockopt TCP_NODELAY: %.100s", strerror(errno));
 142                 return;
 143         }
 144         if (opt == 1) {
 145                 debug2("fd %d is TCP_NODELAY", fd);
 146                 return;
 147         }
 148         opt = 1;
 149         debug2("fd %d setting TCP_NODELAY", fd);
 150         if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof opt) == -1)
 151                 error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
 152 }
 153
 154 /* open a socket in the specified routing domain */
 155 int
 156 socket_rdomain(int domain, int type, int protocol, int rdomain)
 157 {
 158         int sock, ipproto = IPPROTO_IP;
 159
 160         if ((sock = socket(domain, type, protocol)) == -1)
 161                 return (-1);
 162
 163         if (rdomain == -1)
 164                 return (sock);
 165
 166         switch (domain) {
 167 #ifdef IPPROTO_IPV6
 168         case AF_INET6:
 169                 ipproto = IPPROTO_IPV6;
 170                 /* FALLTHROUGH */
 171 #endif
 172         case AF_INET:
 173 #ifdef USE_ROUTINGDOMAIN
 174                 debug2("socket %d af %d setting rdomain %d",
 175                     sock, domain, rdomain);
 176                 if (setsockopt(sock, ipproto, SO_RDOMAIN, &rdomain,
 177                     sizeof(rdomain)) == -1) {
 178                         debug("setsockopt SO_RDOMAIN: %.100s",
 179                             strerror(errno));
 180                         close(sock);
 181                         return (-1);
 182                 }
 183 #endif
 184                 break;
 185         default:
 186                 debug("socket %d af %d does not support rdomain %d",
 187                     sock, domain, rdomain);
 188                 close(sock);
 189                 return (-1);
 190         }
 191
 192         return (sock);
 193 }
 194
 195 /* Characters considered whitespace in strsep calls. */
 196 #define WHITESPACE " \t\r\n"
 197 #define QUOTE   "\""
 198
 199 /* return next token in configuration line */
 200 char *
 201 strdelim(char **s)
 202 {
 203         char *old;
 204         int wspace = 0;
 205
 206         if (*s == NULL)
 207                 return NULL;
 208
 209         old = *s;
 210
 211         *s = strpbrk(*s, WHITESPACE QUOTE "=");
 212         if (*s == NULL)
 213                 return (old);
 214
 215         if (*s[0] == '\"') {
 216                 memmove(*s, *s + 1, strlen(*s)); /* move nul too */
 217                 /* Find matching quote */
 218                 if ((*s = strpbrk(*s, QUOTE)) == NULL) {
 219                         return (NULL);          /* no matching quote */
 220                 } else {
 221                         *s[0] = '\0';
 222                         return (old);
 223                 }
 224         }
 225
 226         /* Allow only one '=' to be skipped */
 227         if (*s[0] == '=')
 228                 wspace = 1;
 229         *s[0] = '\0';
 230
 231         /* Skip any extra whitespace after first token */
 232         *s += strspn(*s + 1, WHITESPACE) + 1;
 233         if (*s[0] == '=' && !wspace)
 234                 *s += strspn(*s + 1, WHITESPACE) + 1;
 235
 236         return (old);
 237 }
 238
 239 struct passwd *
 240 pwcopy(struct passwd *pw)
 241 {
 242         struct passwd *copy = xcalloc(1, sizeof(*copy));
 243
 244         copy->pw_name = xstrdup(pw->pw_name);
 245         copy->pw_passwd = xstrdup(pw->pw_passwd);
 246         copy->pw_gecos = xstrdup(pw->pw_gecos);
 247         copy->pw_uid = pw->pw_uid;
 248         copy->pw_gid = pw->pw_gid;
 249 #ifdef HAVE_PW_EXPIRE_IN_PASSWD
 250         copy->pw_expire = pw->pw_expire;
 251 #endif
 252 #ifdef HAVE_PW_CHANGE_IN_PASSWD
 253         copy->pw_change = pw->pw_change;
 254 #endif
 255 #ifdef HAVE_PW_CLASS_IN_PASSWD
 256         copy->pw_class = xstrdup(pw->pw_class);
 257 #endif
 258         copy->pw_dir = xstrdup(pw->pw_dir);
 259         copy->pw_shell = xstrdup(pw->pw_shell);
 260         return copy;
 261 }
 262
 263 /*
 264  * Convert ASCII string to TCP/IP port number.
 265  * Port must be >=0 and <=65535.
 266  * Return -1 if invalid.
 267  */
 268 int
 269 a2port(const char *s)
 270 {
 271         long long port;
 272         const char *errstr;
 273
 274         port = strtonum(s, 0, 65535, &errstr);
 275         if (errstr != NULL)
 276                 return -1;
 277         return (int)port;
 278 }
 279
 280 #ifdef USE_ROUTINGDOMAIN
 281 int
 282 a2rdomain(const char *s)
 283 {
 284         long long rdomain;
 285         const char *errstr;
 286
 287         rdomain = strtonum(s, 0, RT_TABLEID_MAX, &errstr);
 288         if (errstr != NULL)
 289                 return -1;
 290         return (int)rdomain;
 291 }
 292 #endif
 293
 294 int
 295 a2tun(const char *s, int *remote)
 296 {
 297         const char *errstr = NULL;
 298         char *sp, *ep;
 299         int tun;
 300
 301         if (remote != NULL) {
 302                 *remote = SSH_TUNID_ANY;
 303                 sp = xstrdup(s);
 304                 if ((ep = strchr(sp, ':')) == NULL) {
 305                         xfree(sp);
 306                         return (a2tun(s, NULL));
 307                 }
 308                 ep[0] = '\0'; ep++;
 309                 *remote = a2tun(ep, NULL);
 310                 tun = a2tun(sp, NULL);
 311                 xfree(sp);
 312                 return (*remote == SSH_TUNID_ERR ? *remote : tun);
 313         }
 314
 315         if (strcasecmp(s, "any") == 0)
 316                 return (SSH_TUNID_ANY);
 317
 318         tun = strtonum(s, 0, SSH_TUNID_MAX, &errstr);
 319         if (errstr != NULL)
 320                 return (SSH_TUNID_ERR);
 321
 322         return (tun);
 323 }
 324
 325 #define SECONDS         1
 326 #define MINUTES         (SECONDS * 60)
 327 #define HOURS           (MINUTES * 60)
 328 #define DAYS            (HOURS * 24)
 329 #define WEEKS           (DAYS * 7)
 330
 331 /*
 332  * Convert a time string into seconds; format is
 333  * a sequence of:
 334  *      time[qualifier]
 335  *
 336  * Valid time qualifiers are:
 337  *      <none>  seconds
 338  *      s|S     seconds
 339  *      m|M     minutes
 340  *      h|H     hours
 341  *      d|D     days
 342  *      w|W     weeks
 343  *
 344  * Examples:
 345  *      90m     90 minutes
 346  *      1h30m   90 minutes
 347  *      2d      2 days
 348  *      1w      1 week
 349  *
 350  * Return -1 if time string is invalid.
 351  */
 352 long
 353 convtime(const char *s)
 354 {
 355         long total, secs;
 356         const char *p;
 357         char *endp;
 358
 359         errno = 0;
 360         total = 0;
 361         p = s;
 362
 363         if (p == NULL || *p == '\0')
 364                 return -1;
 365
 366         while (*p) {
 367                 secs = strtol(p, &endp, 10);
 368                 if (p == endp ||
 369                     (errno == ERANGE && (secs == LONG_MIN || secs == LONG_MAX)) ||
 370                     secs < 0)
 371                         return -1;
 372
 373                 switch (*endp++) {
 374                 case '\0':
 375                         endp--;
 376                         break;
 377                 case 's':
 378                 case 'S':
 379                         break;
 380                 case 'm':
 381                 case 'M':
 382                         secs *= MINUTES;
 383                         break;
 384                 case 'h':
 385                 case 'H':
 386                         secs *= HOURS;
 387                         break;
 388                 case 'd':
 389                 case 'D':
 390                         secs *= DAYS;
 391                         break;
 392                 case 'w':
 393                 case 'W':
 394                         secs *= WEEKS;
 395                         break;
 396                 default:
 397                         return -1;
 398                 }
 399                 total += secs;
 400                 if (total < 0)
 401                         return -1;
 402                 p = endp;
 403         }
 404
 405         return total;
 406 }
 407
 408 /*
 409  * Returns a standardized host+port identifier string.
 410  * Caller must free returned string.
 411  */
 412 char *
 413 put_host_port(const char *host, u_short port)
 414 {
 415         char *hoststr;
 416
 417         if (port == 0 || port == SSH_DEFAULT_PORT)
 418                 return(xstrdup(host));
 419         if (asprintf(&hoststr, "[%s]:%d", host, (int)port) < 0)
 420                 fatal("put_host_port: asprintf: %s", strerror(errno));
 421         debug3("put_host_port: %s", hoststr);
 422         return hoststr;
 423 }
 424
 425 /*
 426  * Search for next delimiter between hostnames/addresses and ports.
 427  * Argument may be modified (for termination).
 428  * Returns *cp if parsing succeeds.
 429  * *cp is set to the start of the next delimiter, if one was found.
 430  * If this is the last field, *cp is set to NULL.
 431  */
 432 char *
 433 hpdelim(char **cp)
 434 {
 435         char *s, *old;
 436
 437         if (cp == NULL || *cp == NULL)
 438                 return NULL;
 439
 440         old = s = *cp;
 441         if (*s == '[') {
 442                 if ((s = strchr(s, ']')) == NULL)
 443                         return NULL;
 444                 else
 445                         s++;
 446         } else if ((s = strpbrk(s, ":/")) == NULL)
 447                 s = *cp + strlen(*cp); /* skip to end (see first case below) */
 448
 449         switch (*s) {
 450         case '\0':
 451                 *cp = NULL;     /* no more fields*/
 452                 break;
 453
 454         case ':':
 455         case '/':
 456                 *s = '\0';      /* terminate */
 457                 *cp = s + 1;
 458                 break;
 459
 460         default:
 461                 return NULL;
 462         }
 463
 464         return old;
 465 }
 466
 467 char *
 468 cleanhostname(char *host)
 469 {
 470         if (*host == '[' && host[strlen(host) - 1] == ']') {
 471                 host[strlen(host) - 1] = '\0';
 472                 return (host + 1);
 473         } else
 474                 return host;
 475 }
 476
 477 char *
 478 colon(char *cp)
 479 {
 480         int flag = 0;
 481
 482         if (*cp == ':')         /* Leading colon is part of file name. */
 483                 return (0);
 484         if (*cp == '[')
 485                 flag = 1;
 486
 487         for (; *cp; ++cp) {
 488                 if (*cp == '@' && *(cp+1) == '[')
 489                         flag = 1;
 490                 if (*cp == ']' && *(cp+1) == ':' && flag)
 491                         return (cp+1);
 492                 if (*cp == ':' && !flag)
 493                         return (cp);
 494                 if (*cp == '/')
 495                         return (0);
 496         }
 497         return (0);
 498 }
 499
 500 /* function to assist building execv() arguments */
 501 void
 502 addargs(arglist *args, char *fmt, ...)
 503 {
 504         va_list ap;
 505         char *cp;
 506         u_int nalloc;
 507         int r;
 508
 509         va_start(ap, fmt);
 510         r = vasprintf(&cp, fmt, ap);
 511         va_end(ap);
 512         if (r == -1)
 513                 fatal("addargs: argument too long");
 514
 515         nalloc = args->nalloc;
 516         if (args->list == NULL) {
 517                 nalloc = 32;
 518                 args->num = 0;
 519         } else if (args->num+2 >= nalloc)
 520                 nalloc *= 2;
 521
 522         args->list = xrealloc(args->list, nalloc, sizeof(char *));
 523         args->nalloc = nalloc;
 524         args->list[args->num++] = cp;
 525         args->list[args->num] = NULL;
 526 }
 527
 528 void
 529 replacearg(arglist *args, u_int which, char *fmt, ...)
 530 {
 531         va_list ap;
 532         char *cp;
 533         int r;
 534
 535         va_start(ap, fmt);
 536         r = vasprintf(&cp, fmt, ap);
 537         va_end(ap);
 538         if (r == -1)
 539                 fatal("replacearg: argument too long");
 540
 541         if (which >= args->num)
 542                 fatal("replacearg: tried to replace invalid arg %d >= %d",
 543                     which, args->num);
 544         xfree(args->list[which]);
 545         args->list[which] = cp;
 546 }
 547
 548 void
 549 freeargs(arglist *args)
 550 {
 551         u_int i;
 552
 553         if (args->list != NULL) {
 554                 for (i = 0; i < args->num; i++)
 555                         xfree(args->list[i]);
 556                 xfree(args->list);
 557                 args->nalloc = args->num = 0;
 558                 args->list = NULL;
 559         }
 560 }
 561
 562 /*
 563  * Expands tildes in the file name.  Returns data allocated by xmalloc.
 564  * Warning: this calls getpw*.
 565  */
 566 char *
 567 tilde_expand_filename(const char *filename, uid_t uid)
 568 {
 569         const char *path;
 570         char user[128], ret[MAXPATHLEN];
 571         struct passwd *pw;
 572         u_int len, slash;
 573
 574         if (*filename != '~')
 575                 return (xstrdup(filename));
 576         filename++;
 577
 578         path = strchr(filename, '/');
 579         if (path != NULL && path > filename) {          /* ~user/path */
 580                 slash = path - filename;
 581                 if (slash > sizeof(user) - 1)
 582                         fatal("tilde_expand_filename: ~username too long");
 583                 memcpy(user, filename, slash);
 584                 user[slash] = '\0';
 585                 if ((pw = getpwnam(user)) == NULL)
 586                         fatal("tilde_expand_filename: No such user %s", user);
 587         } else if ((pw = getpwuid(uid)) == NULL)        /* ~/path */
 588                 fatal("tilde_expand_filename: No such uid %ld", (long)uid);
 589
 590         if (strlcpy(ret, pw->pw_dir, sizeof(ret)) >= sizeof(ret))
 591                 fatal("tilde_expand_filename: Path too long");
 592
 593         /* Make sure directory has a trailing '/' */
 594         len = strlen(pw->pw_dir);
 595         if ((len == 0 || pw->pw_dir[len - 1] != '/') &&
 596             strlcat(ret, "/", sizeof(ret)) >= sizeof(ret))
 597                 fatal("tilde_expand_filename: Path too long");
 598
 599         /* Skip leading '/' from specified path */
 600         if (path != NULL)
 601                 filename = path + 1;
 602         if (strlcat(ret, filename, sizeof(ret)) >= sizeof(ret))
 603                 fatal("tilde_expand_filename: Path too long");
 604
 605         return (xstrdup(ret));
 606 }
 607
 608 /*
 609  * Expand a string with a set of %[char] escapes. A number of escapes may be
 610  * specified as (char *escape_chars, char *replacement) pairs. The list must
 611  * be terminated by a NULL escape_char. Returns replaced string in memory
 612  * allocated by xmalloc.
 613  */
 614 char *
 615 percent_expand(const char *string, ...)
 616 {
 617 #define EXPAND_MAX_KEYS 16
 618         u_int num_keys, i, j;
 619         struct {
 620                 const char *key;
 621                 const char *repl;
 622         } keys[EXPAND_MAX_KEYS];
 623         char buf[4096];
 624         va_list ap;
 625
 626         /* Gather keys */
 627         va_start(ap, string);
 628         for (num_keys = 0; num_keys < EXPAND_MAX_KEYS; num_keys++) {
 629                 keys[num_keys].key = va_arg(ap, char *);
 630                 if (keys[num_keys].key == NULL)
 631                         break;
 632                 keys[num_keys].repl = va_arg(ap, char *);
 633                 if (keys[num_keys].repl == NULL)
 634                         fatal("%s: NULL replacement", __func__);
 635         }
 636         if (num_keys == EXPAND_MAX_KEYS && va_arg(ap, char *) != NULL)
 637                 fatal("%s: too many keys", __func__);
 638         va_end(ap);
 639
 640         /* Expand string */
 641         *buf = '\0';
 642         for (i = 0; *string != '\0'; string++) {
 643                 if (*string != '%') {
 644  append:
 645                         buf[i++] = *string;
 646                         if (i >= sizeof(buf))
 647                                 fatal("%s: string too long", __func__);
 648                         buf[i] = '\0';
 649                         continue;
 650                 }
 651                 string++;
 652                 /* %% case */
 653                 if (*string == '%')
 654                         goto append;
 655                 for (j = 0; j < num_keys; j++) {
 656                         if (strchr(keys[j].key, *string) != NULL) {
 657                                 i = strlcat(buf, keys[j].repl, sizeof(buf));
 658                                 if (i >= sizeof(buf))
 659                                         fatal("%s: string too long", __func__);
 660                                 break;
 661                         }
 662                 }
 663                 if (j >= num_keys)
 664                         fatal("%s: unknown key %%%c", __func__, *string);
 665         }
 666         return (xstrdup(buf));
 667 #undef EXPAND_MAX_KEYS
 668 }
 669
 670 /*
 671  * Read an entire line from a public key file into a static buffer, discarding
 672  * lines that exceed the buffer size.  Returns 0 on success, -1 on failure.
 673  */
 674 int
 675 read_keyfile_line(FILE *f, const char *filename, char *buf, size_t bufsz,
 676    u_long *lineno)
 677 {
 678         while (fgets(buf, bufsz, f) != NULL) {
 679                 if (buf[0] == '\0')
 680                         continue;
 681                 (*lineno)++;
 682                 if (buf[strlen(buf) - 1] == '\n' || feof(f)) {
 683                         return 0;
 684                 } else {
 685                         debug("%s: %s line %lu exceeds size limit", __func__,
 686                             filename, *lineno);
 687                         /* discard remainder of line */
 688                         while (fgetc(f) != '\n' && !feof(f))
 689                                 ;       /* nothing */
 690                 }
 691         }
 692         return -1;
 693 }
 694
 695 int
 696 tun_open(int tun, int mode)
 697 {
 698 #if defined(CUSTOM_SYS_TUN_OPEN)
 699         return (sys_tun_open(tun, mode));
 700 #elif defined(SSH_TUN_OPENBSD)
 701         struct ifreq ifr;
 702         char name[100];
 703         int fd = -1, sock;
 704
 705         /* Open the tunnel device */
 706         if (tun <= SSH_TUNID_MAX) {
 707                 snprintf(name, sizeof(name), "/dev/tun%d", tun);
 708                 fd = open(name, O_RDWR);
 709         } else if (tun == SSH_TUNID_ANY) {
 710                 for (tun = 100; tun >= 0; tun--) {
 711                         snprintf(name, sizeof(name), "/dev/tun%d", tun);
 712                         if ((fd = open(name, O_RDWR)) >= 0)
 713                                 break;
 714                 }
 715         } else {
 716                 debug("%s: invalid tunnel %u", __func__, tun);
 717                 return (-1);
 718         }
 719
 720         if (fd < 0) {
 721                 debug("%s: %s open failed: %s", __func__, name, strerror(errno));
 722                 return (-1);
 723         }
 724
 725         debug("%s: %s mode %d fd %d", __func__, name, mode, fd);
 726
 727         /* Set the tunnel device operation mode */
 728         snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "tun%d", tun);
 729         if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
 730                 goto failed;
 731
 732         if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1)
 733                 goto failed;
 734
 735         /* Set interface mode */
 736         ifr.ifr_flags &= ~IFF_UP;
 737         if (mode == SSH_TUNMODE_ETHERNET)
 738                 ifr.ifr_flags |= IFF_LINK0;
 739         else
 740                 ifr.ifr_flags &= ~IFF_LINK0;
 741         if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1)
 742                 goto failed;
 743
 744         /* Bring interface up */
 745         ifr.ifr_flags |= IFF_UP;
 746         if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1)
 747                 goto failed;
 748
 749         close(sock);
 750         return (fd);
 751
 752  failed:
 753         if (fd >= 0)
 754                 close(fd);
 755         if (sock >= 0)
 756                 close(sock);
 757         debug("%s: failed to set %s mode %d: %s", __func__, name,
 758             mode, strerror(errno));
 759         return (-1);
 760 #else
 761         error("Tunnel interfaces are not supported on this platform");
 762         return (-1);
 763 #endif
 764 }
 765
 766 void
 767 sanitise_stdfd(void)
 768 {
 769         int nullfd, dupfd;
 770
 771         if ((nullfd = dupfd = open(_PATH_DEVNULL, O_RDWR)) == -1) {
 772                 fprintf(stderr, "Couldn't open /dev/null: %s\n",
 773                     strerror(errno));
 774                 exit(1);
 775         }
 776         while (++dupfd <= 2) {
 777                 /* Only clobber closed fds */
 778                 if (fcntl(dupfd, F_GETFL, 0) >= 0)
 779                         continue;
 780                 if (dup2(nullfd, dupfd) == -1) {
 781                         fprintf(stderr, "dup2: %s\n", strerror(errno));
 782                         exit(1);
 783                 }
 784         }
 785         if (nullfd > 2)
 786                 close(nullfd);
 787 }
 788
 789 char *
 790 tohex(const void *vp, size_t l)
 791 {
 792         const u_char *p = (const u_char *)vp;
 793         char b[3], *r;
 794         size_t i, hl;
 795
 796         if (l > 65536)
 797                 return xstrdup("tohex: length > 65536");
 798
 799         hl = l * 2 + 1;
 800         r = xcalloc(1, hl);
 801         for (i = 0; i < l; i++) {
 802                 snprintf(b, sizeof(b), "%02x", p[i]);
 803                 strlcat(r, b, hl);
 804         }
 805         return (r);
 806 }
 807
 808 u_int64_t
 809 get_u64(const void *vp)
 810 {
 811         const u_char *p = (const u_char *)vp;
 812         u_int64_t v;
 813
 814         v  = (u_int64_t)p[0] << 56;
 815         v |= (u_int64_t)p[1] << 48;
 816         v |= (u_int64_t)p[2] << 40;
 817         v |= (u_int64_t)p[3] << 32;
 818         v |= (u_int64_t)p[4] << 24;
 819         v |= (u_int64_t)p[5] << 16;
 820         v |= (u_int64_t)p[6] << 8;
 821         v |= (u_int64_t)p[7];
 822
 823         return (v);
 824 }
 825
 826 u_int32_t
 827 get_u32(const void *vp)
 828 {
 829         const u_char *p = (const u_char *)vp;
 830         u_int32_t v;
 831
 832         v  = (u_int32_t)p[0] << 24;
 833         v |= (u_int32_t)p[1] << 16;
 834         v |= (u_int32_t)p[2] << 8;
 835         v |= (u_int32_t)p[3];
 836
 837         return (v);
 838 }
 839
 840 u_int16_t
 841 get_u16(const void *vp)
 842 {
 843         const u_char *p = (const u_char *)vp;
 844         u_int16_t v;
 845
 846         v  = (u_int16_t)p[0] << 8;
 847         v |= (u_int16_t)p[1];
 848
 849         return (v);
 850 }
 851
 852 void
 853 put_u64(void *vp, u_int64_t v)
 854 {
 855         u_char *p = (u_char *)vp;
 856
 857         p[0] = (u_char)(v >> 56) & 0xff;
 858         p[1] = (u_char)(v >> 48) & 0xff;
 859         p[2] = (u_char)(v >> 40) & 0xff;
 860         p[3] = (u_char)(v >> 32) & 0xff;
 861         p[4] = (u_char)(v >> 24) & 0xff;
 862         p[5] = (u_char)(v >> 16) & 0xff;
 863         p[6] = (u_char)(v >> 8) & 0xff;
 864         p[7] = (u_char)v & 0xff;
 865 }
 866
 867 void
 868 put_u32(void *vp, u_int32_t v)
 869 {
 870         u_char *p = (u_char *)vp;
 871
 872         p[0] = (u_char)(v >> 24) & 0xff;
 873         p[1] = (u_char)(v >> 16) & 0xff;
 874         p[2] = (u_char)(v >> 8) & 0xff;
 875         p[3] = (u_char)v & 0xff;
 876 }
 877
 878
 879 void
 880 put_u16(void *vp, u_int16_t v)
 881 {
 882         u_char *p = (u_char *)vp;
 883
 884         p[0] = (u_char)(v >> 8) & 0xff;
 885         p[1] = (u_char)v & 0xff;
 886 }
 887
 888 void
 889 ms_subtract_diff(struct timeval *start, int *ms)
 890 {
 891         struct timeval diff, finish;
 892
 893         gettimeofday(&finish, NULL);
 894         timersub(&finish, start, &diff);
 895         *ms -= (diff.tv_sec * 1000) + (diff.tv_usec / 1000);
 896 }
 897
 898 void
 899 ms_to_timeval(struct timeval *tv, int ms)
 900 {
 901         if (ms < 0)
 902                 ms = 0;
 903         tv->tv_sec = ms / 1000;
 904         tv->tv_usec = (ms % 1000) * 1000;
 905 }
 906
 907 void
 908 sock_set_v6only(int s)
 909 {
 910 #ifdef IPV6_V6ONLY
 911         int on = 1;
 912
 913         debug3("%s: set socket %d IPV6_V6ONLY", __func__, s);
 914         if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) == -1)
 915                 error("setsockopt IPV6_V6ONLY: %s", strerror(errno));
 916 #endif
 917 }