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         case AF_INET6:
 168                 ipproto = IPPROTO_IPV6;
 169                 /* FALLTHROUGH */
 170         case AF_INET:
 171                 debug2("socket %d af %d setting rdomain %d",
 172                     sock, domain, rdomain);
 173                 if (setsockopt(sock, ipproto, SO_RDOMAIN, &rdomain,
 174                     sizeof(rdomain)) == -1) {
 175                         debug("setsockopt SO_RDOMAIN: %.100s",
 176                             strerror(errno));
 177                         close(sock);
 178                         return (-1);
 179                 }
 180                 break;
 181         default:
 182                 debug("socket %d af %d does not support rdomain %d",
 183                     sock, domain, rdomain);
 184                 close(sock);
 185                 return (-1);
 186         }
 187
 188         return (sock);
 189 }
 190
 191 /* Characters considered whitespace in strsep calls. */
 192 #define WHITESPACE " \t\r\n"
 193 #define QUOTE   "\""
 194
 195 /* return next token in configuration line */
 196 char *
 197 strdelim(char **s)
 198 {
 199         char *old;
 200         int wspace = 0;
 201
 202         if (*s == NULL)
 203                 return NULL;
 204
 205         old = *s;
 206
 207         *s = strpbrk(*s, WHITESPACE QUOTE "=");
 208         if (*s == NULL)
 209                 return (old);
 210
 211         if (*s[0] == '\"') {
 212                 memmove(*s, *s + 1, strlen(*s)); /* move nul too */
 213                 /* Find matching quote */
 214                 if ((*s = strpbrk(*s, QUOTE)) == NULL) {
 215                         return (NULL);          /* no matching quote */
 216                 } else {
 217                         *s[0] = '\0';
 218                         return (old);
 219                 }
 220         }
 221
 222         /* Allow only one '=' to be skipped */
 223         if (*s[0] == '=')
 224                 wspace = 1;
 225         *s[0] = '\0';
 226
 227         /* Skip any extra whitespace after first token */
 228         *s += strspn(*s + 1, WHITESPACE) + 1;
 229         if (*s[0] == '=' && !wspace)
 230                 *s += strspn(*s + 1, WHITESPACE) + 1;
 231
 232         return (old);
 233 }
 234
 235 struct passwd *
 236 pwcopy(struct passwd *pw)
 237 {
 238         struct passwd *copy = xcalloc(1, sizeof(*copy));
 239
 240         copy->pw_name = xstrdup(pw->pw_name);
 241         copy->pw_passwd = xstrdup(pw->pw_passwd);
 242         copy->pw_gecos = xstrdup(pw->pw_gecos);
 243         copy->pw_uid = pw->pw_uid;
 244         copy->pw_gid = pw->pw_gid;
 245 #ifdef HAVE_PW_EXPIRE_IN_PASSWD
 246         copy->pw_expire = pw->pw_expire;
 247 #endif
 248 #ifdef HAVE_PW_CHANGE_IN_PASSWD
 249         copy->pw_change = pw->pw_change;
 250 #endif
 251 #ifdef HAVE_PW_CLASS_IN_PASSWD
 252         copy->pw_class = xstrdup(pw->pw_class);
 253 #endif
 254         copy->pw_dir = xstrdup(pw->pw_dir);
 255         copy->pw_shell = xstrdup(pw->pw_shell);
 256         return copy;
 257 }
 258
 259 /*
 260  * Convert ASCII string to TCP/IP port number.
 261  * Port must be >=0 and <=65535.
 262  * Return -1 if invalid.
 263  */
 264 int
 265 a2port(const char *s)
 266 {
 267         long long port;
 268         const char *errstr;
 269
 270         port = strtonum(s, 0, 65535, &errstr);
 271         if (errstr != NULL)
 272                 return -1;
 273         return (int)port;
 274 }
 275
 276 int
 277 a2rdomain(const char *s)
 278 {
 279         long long rdomain;
 280         const char *errstr;
 281
 282         rdomain = strtonum(s, 0, RT_TABLEID_MAX, &errstr);
 283         if (errstr != NULL)
 284                 return -1;
 285         return (int)rdomain;
 286 }
 287
 288 int
 289 a2tun(const char *s, int *remote)
 290 {
 291         const char *errstr = NULL;
 292         char *sp, *ep;
 293         int tun;
 294
 295         if (remote != NULL) {
 296                 *remote = SSH_TUNID_ANY;
 297                 sp = xstrdup(s);
 298                 if ((ep = strchr(sp, ':')) == NULL) {
 299                         xfree(sp);
 300                         return (a2tun(s, NULL));
 301                 }
 302                 ep[0] = '\0'; ep++;
 303                 *remote = a2tun(ep, NULL);
 304                 tun = a2tun(sp, NULL);
 305                 xfree(sp);
 306                 return (*remote == SSH_TUNID_ERR ? *remote : tun);
 307         }
 308
 309         if (strcasecmp(s, "any") == 0)
 310                 return (SSH_TUNID_ANY);
 311
 312         tun = strtonum(s, 0, SSH_TUNID_MAX, &errstr);
 313         if (errstr != NULL)
 314                 return (SSH_TUNID_ERR);
 315
 316         return (tun);
 317 }
 318
 319 #define SECONDS         1
 320 #define MINUTES         (SECONDS * 60)
 321 #define HOURS           (MINUTES * 60)
 322 #define DAYS            (HOURS * 24)
 323 #define WEEKS           (DAYS * 7)
 324
 325 /*
 326  * Convert a time string into seconds; format is
 327  * a sequence of:
 328  *      time[qualifier]
 329  *
 330  * Valid time qualifiers are:
 331  *      <none>  seconds
 332  *      s|S     seconds
 333  *      m|M     minutes
 334  *      h|H     hours
 335  *      d|D     days
 336  *      w|W     weeks
 337  *
 338  * Examples:
 339  *      90m     90 minutes
 340  *      1h30m   90 minutes
 341  *      2d      2 days
 342  *      1w      1 week
 343  *
 344  * Return -1 if time string is invalid.
 345  */
 346 long
 347 convtime(const char *s)
 348 {
 349         long total, secs;
 350         const char *p;
 351         char *endp;
 352
 353         errno = 0;
 354         total = 0;
 355         p = s;
 356
 357         if (p == NULL || *p == '\0')
 358                 return -1;
 359
 360         while (*p) {
 361                 secs = strtol(p, &endp, 10);
 362                 if (p == endp ||
 363                     (errno == ERANGE && (secs == LONG_MIN || secs == LONG_MAX)) ||
 364                     secs < 0)
 365                         return -1;
 366
 367                 switch (*endp++) {
 368                 case '\0':
 369                         endp--;
 370                         break;
 371                 case 's':
 372                 case 'S':
 373                         break;
 374                 case 'm':
 375                 case 'M':
 376                         secs *= MINUTES;
 377                         break;
 378                 case 'h':
 379                 case 'H':
 380                         secs *= HOURS;
 381                         break;
 382                 case 'd':
 383                 case 'D':
 384                         secs *= DAYS;
 385                         break;
 386                 case 'w':
 387                 case 'W':
 388                         secs *= WEEKS;
 389                         break;
 390                 default:
 391                         return -1;
 392                 }
 393                 total += secs;
 394                 if (total < 0)
 395                         return -1;
 396                 p = endp;
 397         }
 398
 399         return total;
 400 }
 401
 402 /*
 403  * Returns a standardized host+port identifier string.
 404  * Caller must free returned string.
 405  */
 406 char *
 407 put_host_port(const char *host, u_short port)
 408 {
 409         char *hoststr;
 410
 411         if (port == 0 || port == SSH_DEFAULT_PORT)
 412                 return(xstrdup(host));
 413         if (asprintf(&hoststr, "[%s]:%d", host, (int)port) < 0)
 414                 fatal("put_host_port: asprintf: %s", strerror(errno));
 415         debug3("put_host_port: %s", hoststr);
 416         return hoststr;
 417 }
 418
 419 /*
 420  * Search for next delimiter between hostnames/addresses and ports.
 421  * Argument may be modified (for termination).
 422  * Returns *cp if parsing succeeds.
 423  * *cp is set to the start of the next delimiter, if one was found.
 424  * If this is the last field, *cp is set to NULL.
 425  */
 426 char *
 427 hpdelim(char **cp)
 428 {
 429         char *s, *old;
 430
 431         if (cp == NULL || *cp == NULL)
 432                 return NULL;
 433
 434         old = s = *cp;
 435         if (*s == '[') {
 436                 if ((s = strchr(s, ']')) == NULL)
 437                         return NULL;
 438                 else
 439                         s++;
 440         } else if ((s = strpbrk(s, ":/")) == NULL)
 441                 s = *cp + strlen(*cp); /* skip to end (see first case below) */
 442
 443         switch (*s) {
 444         case '\0':
 445                 *cp = NULL;     /* no more fields*/
 446                 break;
 447
 448         case ':':
 449         case '/':
 450                 *s = '\0';      /* terminate */
 451                 *cp = s + 1;
 452                 break;
 453
 454         default:
 455                 return NULL;
 456         }
 457
 458         return old;
 459 }
 460
 461 char *
 462 cleanhostname(char *host)
 463 {
 464         if (*host == '[' && host[strlen(host) - 1] == ']') {
 465                 host[strlen(host) - 1] = '\0';
 466                 return (host + 1);
 467         } else
 468                 return host;
 469 }
 470
 471 char *
 472 colon(char *cp)
 473 {
 474         int flag = 0;
 475
 476         if (*cp == ':')         /* Leading colon is part of file name. */
 477                 return (0);
 478         if (*cp == '[')
 479                 flag = 1;
 480
 481         for (; *cp; ++cp) {
 482                 if (*cp == '@' && *(cp+1) == '[')
 483                         flag = 1;
 484                 if (*cp == ']' && *(cp+1) == ':' && flag)
 485                         return (cp+1);
 486                 if (*cp == ':' && !flag)
 487                         return (cp);
 488                 if (*cp == '/')
 489                         return (0);
 490         }
 491         return (0);
 492 }
 493
 494 /* function to assist building execv() arguments */
 495 void
 496 addargs(arglist *args, char *fmt, ...)
 497 {
 498         va_list ap;
 499         char *cp;
 500         u_int nalloc;
 501         int r;
 502
 503         va_start(ap, fmt);
 504         r = vasprintf(&cp, fmt, ap);
 505         va_end(ap);
 506         if (r == -1)
 507                 fatal("addargs: argument too long");
 508
 509         nalloc = args->nalloc;
 510         if (args->list == NULL) {
 511                 nalloc = 32;
 512                 args->num = 0;
 513         } else if (args->num+2 >= nalloc)
 514                 nalloc *= 2;
 515
 516         args->list = xrealloc(args->list, nalloc, sizeof(char *));
 517         args->nalloc = nalloc;
 518         args->list[args->num++] = cp;
 519         args->list[args->num] = NULL;
 520 }
 521
 522 void
 523 replacearg(arglist *args, u_int which, char *fmt, ...)
 524 {
 525         va_list ap;
 526         char *cp;
 527         int r;
 528
 529         va_start(ap, fmt);
 530         r = vasprintf(&cp, fmt, ap);
 531         va_end(ap);
 532         if (r == -1)
 533                 fatal("replacearg: argument too long");
 534
 535         if (which >= args->num)
 536                 fatal("replacearg: tried to replace invalid arg %d >= %d",
 537                     which, args->num);
 538         xfree(args->list[which]);
 539         args->list[which] = cp;
 540 }
 541
 542 void
 543 freeargs(arglist *args)
 544 {
 545         u_int i;
 546
 547         if (args->list != NULL) {
 548                 for (i = 0; i < args->num; i++)
 549                         xfree(args->list[i]);
 550                 xfree(args->list);
 551                 args->nalloc = args->num = 0;
 552                 args->list = NULL;
 553         }
 554 }
 555
 556 /*
 557  * Expands tildes in the file name.  Returns data allocated by xmalloc.
 558  * Warning: this calls getpw*.
 559  */
 560 char *
 561 tilde_expand_filename(const char *filename, uid_t uid)
 562 {
 563         const char *path;
 564         char user[128], ret[MAXPATHLEN];
 565         struct passwd *pw;
 566         u_int len, slash;
 567
 568         if (*filename != '~')
 569                 return (xstrdup(filename));
 570         filename++;
 571
 572         path = strchr(filename, '/');
 573         if (path != NULL && path > filename) {          /* ~user/path */
 574                 slash = path - filename;
 575                 if (slash > sizeof(user) - 1)
 576                         fatal("tilde_expand_filename: ~username too long");
 577                 memcpy(user, filename, slash);
 578                 user[slash] = '\0';
 579                 if ((pw = getpwnam(user)) == NULL)
 580                         fatal("tilde_expand_filename: No such user %s", user);
 581         } else if ((pw = getpwuid(uid)) == NULL)        /* ~/path */
 582                 fatal("tilde_expand_filename: No such uid %ld", (long)uid);
 583
 584         if (strlcpy(ret, pw->pw_dir, sizeof(ret)) >= sizeof(ret))
 585                 fatal("tilde_expand_filename: Path too long");
 586
 587         /* Make sure directory has a trailing '/' */
 588         len = strlen(pw->pw_dir);
 589         if ((len == 0 || pw->pw_dir[len - 1] != '/') &&
 590             strlcat(ret, "/", sizeof(ret)) >= sizeof(ret))
 591                 fatal("tilde_expand_filename: Path too long");
 592
 593         /* Skip leading '/' from specified path */
 594         if (path != NULL)
 595                 filename = path + 1;
 596         if (strlcat(ret, filename, sizeof(ret)) >= sizeof(ret))
 597                 fatal("tilde_expand_filename: Path too long");
 598
 599         return (xstrdup(ret));
 600 }
 601
 602 /*
 603  * Expand a string with a set of %[char] escapes. A number of escapes may be
 604  * specified as (char *escape_chars, char *replacement) pairs. The list must
 605  * be terminated by a NULL escape_char. Returns replaced string in memory
 606  * allocated by xmalloc.
 607  */
 608 char *
 609 percent_expand(const char *string, ...)
 610 {
 611 #define EXPAND_MAX_KEYS 16
 612         u_int num_keys, i, j;
 613         struct {
 614                 const char *key;
 615                 const char *repl;
 616         } keys[EXPAND_MAX_KEYS];
 617         char buf[4096];
 618         va_list ap;
 619
 620         /* Gather keys */
 621         va_start(ap, string);
 622         for (num_keys = 0; num_keys < EXPAND_MAX_KEYS; num_keys++) {
 623                 keys[num_keys].key = va_arg(ap, char *);
 624                 if (keys[num_keys].key == NULL)
 625                         break;
 626                 keys[num_keys].repl = va_arg(ap, char *);
 627                 if (keys[num_keys].repl == NULL)
 628                         fatal("%s: NULL replacement", __func__);
 629         }
 630         if (num_keys == EXPAND_MAX_KEYS && va_arg(ap, char *) != NULL)
 631                 fatal("%s: too many keys", __func__);
 632         va_end(ap);
 633
 634         /* Expand string */
 635         *buf = '\0';
 636         for (i = 0; *string != '\0'; string++) {
 637                 if (*string != '%') {
 638  append:
 639                         buf[i++] = *string;
 640                         if (i >= sizeof(buf))
 641                                 fatal("%s: string too long", __func__);
 642                         buf[i] = '\0';
 643                         continue;
 644                 }
 645                 string++;
 646                 /* %% case */
 647                 if (*string == '%')
 648                         goto append;
 649                 for (j = 0; j < num_keys; j++) {
 650                         if (strchr(keys[j].key, *string) != NULL) {
 651                                 i = strlcat(buf, keys[j].repl, sizeof(buf));
 652                                 if (i >= sizeof(buf))
 653                                         fatal("%s: string too long", __func__);
 654                                 break;
 655                         }
 656                 }
 657                 if (j >= num_keys)
 658                         fatal("%s: unknown key %%%c", __func__, *string);
 659         }
 660         return (xstrdup(buf));
 661 #undef EXPAND_MAX_KEYS
 662 }
 663
 664 /*
 665  * Read an entire line from a public key file into a static buffer, discarding
 666  * lines that exceed the buffer size.  Returns 0 on success, -1 on failure.
 667  */
 668 int
 669 read_keyfile_line(FILE *f, const char *filename, char *buf, size_t bufsz,
 670    u_long *lineno)
 671 {
 672         while (fgets(buf, bufsz, f) != NULL) {
 673                 if (buf[0] == '\0')
 674                         continue;
 675                 (*lineno)++;
 676                 if (buf[strlen(buf) - 1] == '\n' || feof(f)) {
 677                         return 0;
 678                 } else {
 679                         debug("%s: %s line %lu exceeds size limit", __func__,
 680                             filename, *lineno);
 681                         /* discard remainder of line */
 682                         while (fgetc(f) != '\n' && !feof(f))
 683                                 ;       /* nothing */
 684                 }
 685         }
 686         return -1;
 687 }
 688
 689 int
 690 tun_open(int tun, int mode)
 691 {
 692 #if defined(CUSTOM_SYS_TUN_OPEN)
 693         return (sys_tun_open(tun, mode));
 694 #elif defined(SSH_TUN_OPENBSD)
 695         struct ifreq ifr;
 696         char name[100];
 697         int fd = -1, sock;
 698
 699         /* Open the tunnel device */
 700         if (tun <= SSH_TUNID_MAX) {
 701                 snprintf(name, sizeof(name), "/dev/tun%d", tun);
 702                 fd = open(name, O_RDWR);
 703         } else if (tun == SSH_TUNID_ANY) {
 704                 for (tun = 100; tun >= 0; tun--) {
 705                         snprintf(name, sizeof(name), "/dev/tun%d", tun);
 706                         if ((fd = open(name, O_RDWR)) >= 0)
 707                                 break;
 708                 }
 709         } else {
 710                 debug("%s: invalid tunnel %u", __func__, tun);
 711                 return (-1);
 712         }
 713
 714         if (fd < 0) {
 715                 debug("%s: %s open failed: %s", __func__, name, strerror(errno));
 716                 return (-1);
 717         }
 718
 719         debug("%s: %s mode %d fd %d", __func__, name, mode, fd);
 720
 721         /* Set the tunnel device operation mode */
 722         snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "tun%d", tun);
 723         if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
 724                 goto failed;
 725
 726         if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1)
 727                 goto failed;
 728
 729         /* Set interface mode */
 730         ifr.ifr_flags &= ~IFF_UP;
 731         if (mode == SSH_TUNMODE_ETHERNET)
 732                 ifr.ifr_flags |= IFF_LINK0;
 733         else
 734                 ifr.ifr_flags &= ~IFF_LINK0;
 735         if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1)
 736                 goto failed;
 737
 738         /* Bring interface up */
 739         ifr.ifr_flags |= IFF_UP;
 740         if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1)
 741                 goto failed;
 742
 743         close(sock);
 744         return (fd);
 745
 746  failed:
 747         if (fd >= 0)
 748                 close(fd);
 749         if (sock >= 0)
 750                 close(sock);
 751         debug("%s: failed to set %s mode %d: %s", __func__, name,
 752             mode, strerror(errno));
 753         return (-1);
 754 #else
 755         error("Tunnel interfaces are not supported on this platform");
 756         return (-1);
 757 #endif
 758 }
 759
 760 void
 761 sanitise_stdfd(void)
 762 {
 763         int nullfd, dupfd;
 764
 765         if ((nullfd = dupfd = open(_PATH_DEVNULL, O_RDWR)) == -1) {
 766                 fprintf(stderr, "Couldn't open /dev/null: %s\n",
 767                     strerror(errno));
 768                 exit(1);
 769         }
 770         while (++dupfd <= 2) {
 771                 /* Only clobber closed fds */
 772                 if (fcntl(dupfd, F_GETFL, 0) >= 0)
 773                         continue;
 774                 if (dup2(nullfd, dupfd) == -1) {
 775                         fprintf(stderr, "dup2: %s\n", strerror(errno));
 776                         exit(1);
 777                 }
 778         }
 779         if (nullfd > 2)
 780                 close(nullfd);
 781 }
 782
 783 char *
 784 tohex(const void *vp, size_t l)
 785 {
 786         const u_char *p = (const u_char *)vp;
 787         char b[3], *r;
 788         size_t i, hl;
 789
 790         if (l > 65536)
 791                 return xstrdup("tohex: length > 65536");
 792
 793         hl = l * 2 + 1;
 794         r = xcalloc(1, hl);
 795         for (i = 0; i < l; i++) {
 796                 snprintf(b, sizeof(b), "%02x", p[i]);
 797                 strlcat(r, b, hl);
 798         }
 799         return (r);
 800 }
 801
 802 u_int64_t
 803 get_u64(const void *vp)
 804 {
 805         const u_char *p = (const u_char *)vp;
 806         u_int64_t v;
 807
 808         v  = (u_int64_t)p[0] << 56;
 809         v |= (u_int64_t)p[1] << 48;
 810         v |= (u_int64_t)p[2] << 40;
 811         v |= (u_int64_t)p[3] << 32;
 812         v |= (u_int64_t)p[4] << 24;
 813         v |= (u_int64_t)p[5] << 16;
 814         v |= (u_int64_t)p[6] << 8;
 815         v |= (u_int64_t)p[7];
 816
 817         return (v);
 818 }
 819
 820 u_int32_t
 821 get_u32(const void *vp)
 822 {
 823         const u_char *p = (const u_char *)vp;
 824         u_int32_t v;
 825
 826         v  = (u_int32_t)p[0] << 24;
 827         v |= (u_int32_t)p[1] << 16;
 828         v |= (u_int32_t)p[2] << 8;
 829         v |= (u_int32_t)p[3];
 830
 831         return (v);
 832 }
 833
 834 u_int16_t
 835 get_u16(const void *vp)
 836 {
 837         const u_char *p = (const u_char *)vp;
 838         u_int16_t v;
 839
 840         v  = (u_int16_t)p[0] << 8;
 841         v |= (u_int16_t)p[1];
 842
 843         return (v);
 844 }
 845
 846 void
 847 put_u64(void *vp, u_int64_t v)
 848 {
 849         u_char *p = (u_char *)vp;
 850
 851         p[0] = (u_char)(v >> 56) & 0xff;
 852         p[1] = (u_char)(v >> 48) & 0xff;
 853         p[2] = (u_char)(v >> 40) & 0xff;
 854         p[3] = (u_char)(v >> 32) & 0xff;
 855         p[4] = (u_char)(v >> 24) & 0xff;
 856         p[5] = (u_char)(v >> 16) & 0xff;
 857         p[6] = (u_char)(v >> 8) & 0xff;
 858         p[7] = (u_char)v & 0xff;
 859 }
 860
 861 void
 862 put_u32(void *vp, u_int32_t v)
 863 {
 864         u_char *p = (u_char *)vp;
 865
 866         p[0] = (u_char)(v >> 24) & 0xff;
 867         p[1] = (u_char)(v >> 16) & 0xff;
 868         p[2] = (u_char)(v >> 8) & 0xff;
 869         p[3] = (u_char)v & 0xff;
 870 }
 871
 872
 873 void
 874 put_u16(void *vp, u_int16_t v)
 875 {
 876         u_char *p = (u_char *)vp;
 877
 878         p[0] = (u_char)(v >> 8) & 0xff;
 879         p[1] = (u_char)v & 0xff;
 880 }
 881
 882 void
 883 ms_subtract_diff(struct timeval *start, int *ms)
 884 {
 885         struct timeval diff, finish;
 886
 887         gettimeofday(&finish, NULL);
 888         timersub(&finish, start, &diff);
 889         *ms -= (diff.tv_sec * 1000) + (diff.tv_usec / 1000);
 890 }
 891
 892 void
 893 ms_to_timeval(struct timeval *tv, int ms)
 894 {
 895         if (ms < 0)
 896                 ms = 0;
 897         tv->tv_sec = ms / 1000;
 898         tv->tv_usec = (ms % 1000) * 1000;
 899 }
 900
 901 void
 902 sock_set_v6only(int s)
 903 {
 904 #ifdef IPV6_V6ONLY
 905         int on = 1;
 906
 907         debug3("%s: set socket %d IPV6_V6ONLY", __func__, s);
 908         if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) == -1)
 909                 error("setsockopt IPV6_V6ONLY: %s", strerror(errno));
 910 #endif
 911 }