misc.c

   1 /* $OpenBSD: misc.c,v 1.82 2010/09/24 13:33:00 matthew 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 /* Characters considered whitespace in strsep calls. */
 155 #define WHITESPACE " \t\r\n"
 156 #define QUOTE   "\""
 157
 158 /* return next token in configuration line */
 159 char *
 160 strdelim(char **s)
 161 {
 162         char *old;
 163         int wspace = 0;
 164
 165         if (*s == NULL)
 166                 return NULL;
 167
 168         old = *s;
 169
 170         *s = strpbrk(*s, WHITESPACE QUOTE "=");
 171         if (*s == NULL)
 172                 return (old);
 173
 174         if (*s[0] == '\"') {
 175                 memmove(*s, *s + 1, strlen(*s)); /* move nul too */
 176                 /* Find matching quote */
 177                 if ((*s = strpbrk(*s, QUOTE)) == NULL) {
 178                         return (NULL);          /* no matching quote */
 179                 } else {
 180                         *s[0] = '\0';
 181                         *s += strspn(*s + 1, WHITESPACE) + 1;
 182                         return (old);
 183                 }
 184         }
 185
 186         /* Allow only one '=' to be skipped */
 187         if (*s[0] == '=')
 188                 wspace = 1;
 189         *s[0] = '\0';
 190
 191         /* Skip any extra whitespace after first token */
 192         *s += strspn(*s + 1, WHITESPACE) + 1;
 193         if (*s[0] == '=' && !wspace)
 194                 *s += strspn(*s + 1, WHITESPACE) + 1;
 195
 196         return (old);
 197 }
 198
 199 struct passwd *
 200 pwcopy(struct passwd *pw)
 201 {
 202         struct passwd *copy = xcalloc(1, sizeof(*copy));
 203
 204         copy->pw_name = xstrdup(pw->pw_name);
 205         copy->pw_passwd = xstrdup(pw->pw_passwd);
 206         copy->pw_gecos = xstrdup(pw->pw_gecos);
 207         copy->pw_uid = pw->pw_uid;
 208         copy->pw_gid = pw->pw_gid;
 209 #ifdef HAVE_PW_EXPIRE_IN_PASSWD
 210         copy->pw_expire = pw->pw_expire;
 211 #endif
 212 #ifdef HAVE_PW_CHANGE_IN_PASSWD
 213         copy->pw_change = pw->pw_change;
 214 #endif
 215 #ifdef HAVE_PW_CLASS_IN_PASSWD
 216         copy->pw_class = xstrdup(pw->pw_class);
 217 #endif
 218         copy->pw_dir = xstrdup(pw->pw_dir);
 219         copy->pw_shell = xstrdup(pw->pw_shell);
 220         return copy;
 221 }
 222
 223 /*
 224  * Convert ASCII string to TCP/IP port number.
 225  * Port must be >=0 and <=65535.
 226  * Return -1 if invalid.
 227  */
 228 int
 229 a2port(const char *s)
 230 {
 231         long long port;
 232         const char *errstr;
 233
 234         port = strtonum(s, 0, 65535, &errstr);
 235         if (errstr != NULL)
 236                 return -1;
 237         return (int)port;
 238 }
 239
 240 int
 241 a2tun(const char *s, int *remote)
 242 {
 243         const char *errstr = NULL;
 244         char *sp, *ep;
 245         int tun;
 246
 247         if (remote != NULL) {
 248                 *remote = SSH_TUNID_ANY;
 249                 sp = xstrdup(s);
 250                 if ((ep = strchr(sp, ':')) == NULL) {
 251                         xfree(sp);
 252                         return (a2tun(s, NULL));
 253                 }
 254                 ep[0] = '\0'; ep++;
 255                 *remote = a2tun(ep, NULL);
 256                 tun = a2tun(sp, NULL);
 257                 xfree(sp);
 258                 return (*remote == SSH_TUNID_ERR ? *remote : tun);
 259         }
 260
 261         if (strcasecmp(s, "any") == 0)
 262                 return (SSH_TUNID_ANY);
 263
 264         tun = strtonum(s, 0, SSH_TUNID_MAX, &errstr);
 265         if (errstr != NULL)
 266                 return (SSH_TUNID_ERR);
 267
 268         return (tun);
 269 }
 270
 271 #define SECONDS         1
 272 #define MINUTES         (SECONDS * 60)
 273 #define HOURS           (MINUTES * 60)
 274 #define DAYS            (HOURS * 24)
 275 #define WEEKS           (DAYS * 7)
 276
 277 /*
 278  * Convert a time string into seconds; format is
 279  * a sequence of:
 280  *      time[qualifier]
 281  *
 282  * Valid time qualifiers are:
 283  *      <none>  seconds
 284  *      s|S     seconds
 285  *      m|M     minutes
 286  *      h|H     hours
 287  *      d|D     days
 288  *      w|W     weeks
 289  *
 290  * Examples:
 291  *      90m     90 minutes
 292  *      1h30m   90 minutes
 293  *      2d      2 days
 294  *      1w      1 week
 295  *
 296  * Return -1 if time string is invalid.
 297  */
 298 long
 299 convtime(const char *s)
 300 {
 301         long total, secs;
 302         const char *p;
 303         char *endp;
 304
 305         errno = 0;
 306         total = 0;
 307         p = s;
 308
 309         if (p == NULL || *p == '\0')
 310                 return -1;
 311
 312         while (*p) {
 313                 secs = strtol(p, &endp, 10);
 314                 if (p == endp ||
 315                     (errno == ERANGE && (secs == LONG_MIN || secs == LONG_MAX)) ||
 316                     secs < 0)
 317                         return -1;
 318
 319                 switch (*endp++) {
 320                 case '\0':
 321                         endp--;
 322                         break;
 323                 case 's':
 324                 case 'S':
 325                         break;
 326                 case 'm':
 327                 case 'M':
 328                         secs *= MINUTES;
 329                         break;
 330                 case 'h':
 331                 case 'H':
 332                         secs *= HOURS;
 333                         break;
 334                 case 'd':
 335                 case 'D':
 336                         secs *= DAYS;
 337                         break;
 338                 case 'w':
 339                 case 'W':
 340                         secs *= WEEKS;
 341                         break;
 342                 default:
 343                         return -1;
 344                 }
 345                 total += secs;
 346                 if (total < 0)
 347                         return -1;
 348                 p = endp;
 349         }
 350
 351         return total;
 352 }
 353
 354 /*
 355  * Returns a standardized host+port identifier string.
 356  * Caller must free returned string.
 357  */
 358 char *
 359 put_host_port(const char *host, u_short port)
 360 {
 361         char *hoststr;
 362
 363         if (port == 0 || port == SSH_DEFAULT_PORT)
 364                 return(xstrdup(host));
 365         if (asprintf(&hoststr, "[%s]:%d", host, (int)port) < 0)
 366                 fatal("put_host_port: asprintf: %s", strerror(errno));
 367         debug3("put_host_port: %s", hoststr);
 368         return hoststr;
 369 }
 370
 371 /*
 372  * Search for next delimiter between hostnames/addresses and ports.
 373  * Argument may be modified (for termination).
 374  * Returns *cp if parsing succeeds.
 375  * *cp is set to the start of the next delimiter, if one was found.
 376  * If this is the last field, *cp is set to NULL.
 377  */
 378 char *
 379 hpdelim(char **cp)
 380 {
 381         char *s, *old;
 382
 383         if (cp == NULL || *cp == NULL)
 384                 return NULL;
 385
 386         old = s = *cp;
 387         if (*s == '[') {
 388                 if ((s = strchr(s, ']')) == NULL)
 389                         return NULL;
 390                 else
 391                         s++;
 392         } else if ((s = strpbrk(s, ":/")) == NULL)
 393                 s = *cp + strlen(*cp); /* skip to end (see first case below) */
 394
 395         switch (*s) {
 396         case '\0':
 397                 *cp = NULL;     /* no more fields*/
 398                 break;
 399
 400         case ':':
 401         case '/':
 402                 *s = '\0';      /* terminate */
 403                 *cp = s + 1;
 404                 break;
 405
 406         default:
 407                 return NULL;
 408         }
 409
 410         return old;
 411 }
 412
 413 char *
 414 cleanhostname(char *host)
 415 {
 416         if (*host == '[' && host[strlen(host) - 1] == ']') {
 417                 host[strlen(host) - 1] = '\0';
 418                 return (host + 1);
 419         } else
 420                 return host;
 421 }
 422
 423 char *
 424 colon(char *cp)
 425 {
 426         int flag = 0;
 427
 428         if (*cp == ':')         /* Leading colon is part of file name. */
 429                 return NULL;
 430         if (*cp == '[')
 431                 flag = 1;
 432
 433         for (; *cp; ++cp) {
 434                 if (*cp == '@' && *(cp+1) == '[')
 435                         flag = 1;
 436                 if (*cp == ']' && *(cp+1) == ':' && flag)
 437                         return (cp+1);
 438                 if (*cp == ':' && !flag)
 439                         return (cp);
 440                 if (*cp == '/')
 441                         return NULL;
 442         }
 443         return NULL;
 444 }
 445
 446 /* function to assist building execv() arguments */
 447 void
 448 addargs(arglist *args, char *fmt, ...)
 449 {
 450         va_list ap;
 451         char *cp;
 452         u_int nalloc;
 453         int r;
 454
 455         va_start(ap, fmt);
 456         r = vasprintf(&cp, fmt, ap);
 457         va_end(ap);
 458         if (r == -1)
 459                 fatal("addargs: argument too long");
 460
 461         nalloc = args->nalloc;
 462         if (args->list == NULL) {
 463                 nalloc = 32;
 464                 args->num = 0;
 465         } else if (args->num+2 >= nalloc)
 466                 nalloc *= 2;
 467
 468         args->list = xrealloc(args->list, nalloc, sizeof(char *));
 469         args->nalloc = nalloc;
 470         args->list[args->num++] = cp;
 471         args->list[args->num] = NULL;
 472 }
 473
 474 void
 475 replacearg(arglist *args, u_int which, char *fmt, ...)
 476 {
 477         va_list ap;
 478         char *cp;
 479         int r;
 480
 481         va_start(ap, fmt);
 482         r = vasprintf(&cp, fmt, ap);
 483         va_end(ap);
 484         if (r == -1)
 485                 fatal("replacearg: argument too long");
 486
 487         if (which >= args->num)
 488                 fatal("replacearg: tried to replace invalid arg %d >= %d",
 489                     which, args->num);
 490         xfree(args->list[which]);
 491         args->list[which] = cp;
 492 }
 493
 494 void
 495 freeargs(arglist *args)
 496 {
 497         u_int i;
 498
 499         if (args->list != NULL) {
 500                 for (i = 0; i < args->num; i++)
 501                         xfree(args->list[i]);
 502                 xfree(args->list);
 503                 args->nalloc = args->num = 0;
 504                 args->list = NULL;
 505         }
 506 }
 507
 508 /*
 509  * Expands tildes in the file name.  Returns data allocated by xmalloc.
 510  * Warning: this calls getpw*.
 511  */
 512 char *
 513 tilde_expand_filename(const char *filename, uid_t uid)
 514 {
 515         const char *path;
 516         char user[128], ret[MAXPATHLEN];
 517         struct passwd *pw;
 518         u_int len, slash;
 519
 520         if (*filename != '~')
 521                 return (xstrdup(filename));
 522         filename++;
 523
 524         path = strchr(filename, '/');
 525         if (path != NULL && path > filename) {          /* ~user/path */
 526                 slash = path - filename;
 527                 if (slash > sizeof(user) - 1)
 528                         fatal("tilde_expand_filename: ~username too long");
 529                 memcpy(user, filename, slash);
 530                 user[slash] = '\0';
 531                 if ((pw = getpwnam(user)) == NULL)
 532                         fatal("tilde_expand_filename: No such user %s", user);
 533         } else if ((pw = getpwuid(uid)) == NULL)        /* ~/path */
 534                 fatal("tilde_expand_filename: No such uid %ld", (long)uid);
 535
 536         if (strlcpy(ret, pw->pw_dir, sizeof(ret)) >= sizeof(ret))
 537                 fatal("tilde_expand_filename: Path too long");
 538
 539         /* Make sure directory has a trailing '/' */
 540         len = strlen(pw->pw_dir);
 541         if ((len == 0 || pw->pw_dir[len - 1] != '/') &&
 542             strlcat(ret, "/", sizeof(ret)) >= sizeof(ret))
 543                 fatal("tilde_expand_filename: Path too long");
 544
 545         /* Skip leading '/' from specified path */
 546         if (path != NULL)
 547                 filename = path + 1;
 548         if (strlcat(ret, filename, sizeof(ret)) >= sizeof(ret))
 549                 fatal("tilde_expand_filename: Path too long");
 550
 551         return (xstrdup(ret));
 552 }
 553
 554 /*
 555  * Expand a string with a set of %[char] escapes. A number of escapes may be
 556  * specified as (char *escape_chars, char *replacement) pairs. The list must
 557  * be terminated by a NULL escape_char. Returns replaced string in memory
 558  * allocated by xmalloc.
 559  */
 560 char *
 561 percent_expand(const char *string, ...)
 562 {
 563 #define EXPAND_MAX_KEYS 16
 564         u_int num_keys, i, j;
 565         struct {
 566                 const char *key;
 567                 const char *repl;
 568         } keys[EXPAND_MAX_KEYS];
 569         char buf[4096];
 570         va_list ap;
 571
 572         /* Gather keys */
 573         va_start(ap, string);
 574         for (num_keys = 0; num_keys < EXPAND_MAX_KEYS; num_keys++) {
 575                 keys[num_keys].key = va_arg(ap, char *);
 576                 if (keys[num_keys].key == NULL)
 577                         break;
 578                 keys[num_keys].repl = va_arg(ap, char *);
 579                 if (keys[num_keys].repl == NULL)
 580                         fatal("%s: NULL replacement", __func__);
 581         }
 582         if (num_keys == EXPAND_MAX_KEYS && va_arg(ap, char *) != NULL)
 583                 fatal("%s: too many keys", __func__);
 584         va_end(ap);
 585
 586         /* Expand string */
 587         *buf = '\0';
 588         for (i = 0; *string != '\0'; string++) {
 589                 if (*string != '%') {
 590  append:
 591                         buf[i++] = *string;
 592                         if (i >= sizeof(buf))
 593                                 fatal("%s: string too long", __func__);
 594                         buf[i] = '\0';
 595                         continue;
 596                 }
 597                 string++;
 598                 /* %% case */
 599                 if (*string == '%')
 600                         goto append;
 601                 for (j = 0; j < num_keys; j++) {
 602                         if (strchr(keys[j].key, *string) != NULL) {
 603                                 i = strlcat(buf, keys[j].repl, sizeof(buf));
 604                                 if (i >= sizeof(buf))
 605                                         fatal("%s: string too long", __func__);
 606                                 break;
 607                         }
 608                 }
 609                 if (j >= num_keys)
 610                         fatal("%s: unknown key %%%c", __func__, *string);
 611         }
 612         return (xstrdup(buf));
 613 #undef EXPAND_MAX_KEYS
 614 }
 615
 616 /*
 617  * Read an entire line from a public key file into a static buffer, discarding
 618  * lines that exceed the buffer size.  Returns 0 on success, -1 on failure.
 619  */
 620 int
 621 read_keyfile_line(FILE *f, const char *filename, char *buf, size_t bufsz,
 622    u_long *lineno)
 623 {
 624         while (fgets(buf, bufsz, f) != NULL) {
 625                 if (buf[0] == '\0')
 626                         continue;
 627                 (*lineno)++;
 628                 if (buf[strlen(buf) - 1] == '\n' || feof(f)) {
 629                         return 0;
 630                 } else {
 631                         debug("%s: %s line %lu exceeds size limit", __func__,
 632                             filename, *lineno);
 633                         /* discard remainder of line */
 634                         while (fgetc(f) != '\n' && !feof(f))
 635                                 ;       /* nothing */
 636                 }
 637         }
 638         return -1;
 639 }
 640
 641 int
 642 tun_open(int tun, int mode)
 643 {
 644 #if defined(CUSTOM_SYS_TUN_OPEN)
 645         return (sys_tun_open(tun, mode));
 646 #elif defined(SSH_TUN_OPENBSD)
 647         struct ifreq ifr;
 648         char name[100];
 649         int fd = -1, sock;
 650
 651         /* Open the tunnel device */
 652         if (tun <= SSH_TUNID_MAX) {
 653                 snprintf(name, sizeof(name), "/dev/tun%d", tun);
 654                 fd = open(name, O_RDWR);
 655         } else if (tun == SSH_TUNID_ANY) {
 656                 for (tun = 100; tun >= 0; tun--) {
 657                         snprintf(name, sizeof(name), "/dev/tun%d", tun);
 658                         if ((fd = open(name, O_RDWR)) >= 0)
 659                                 break;
 660                 }
 661         } else {
 662                 debug("%s: invalid tunnel %u", __func__, tun);
 663                 return (-1);
 664         }
 665
 666         if (fd < 0) {
 667                 debug("%s: %s open failed: %s", __func__, name, strerror(errno));
 668                 return (-1);
 669         }
 670
 671         debug("%s: %s mode %d fd %d", __func__, name, mode, fd);
 672
 673         /* Set the tunnel device operation mode */
 674         snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "tun%d", tun);
 675         if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
 676                 goto failed;
 677
 678         if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1)
 679                 goto failed;
 680
 681         /* Set interface mode */
 682         ifr.ifr_flags &= ~IFF_UP;
 683         if (mode == SSH_TUNMODE_ETHERNET)
 684                 ifr.ifr_flags |= IFF_LINK0;
 685         else
 686                 ifr.ifr_flags &= ~IFF_LINK0;
 687         if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1)
 688                 goto failed;
 689
 690         /* Bring interface up */
 691         ifr.ifr_flags |= IFF_UP;
 692         if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1)
 693                 goto failed;
 694
 695         close(sock);
 696         return (fd);
 697
 698  failed:
 699         if (fd >= 0)
 700                 close(fd);
 701         if (sock >= 0)
 702                 close(sock);
 703         debug("%s: failed to set %s mode %d: %s", __func__, name,
 704             mode, strerror(errno));
 705         return (-1);
 706 #else
 707         error("Tunnel interfaces are not supported on this platform");
 708         return (-1);
 709 #endif
 710 }
 711
 712 void
 713 sanitise_stdfd(void)
 714 {
 715         int nullfd, dupfd;
 716
 717         if ((nullfd = dupfd = open(_PATH_DEVNULL, O_RDWR)) == -1) {
 718                 fprintf(stderr, "Couldn't open /dev/null: %s\n",
 719                     strerror(errno));
 720                 exit(1);
 721         }
 722         while (++dupfd <= 2) {
 723                 /* Only clobber closed fds */
 724                 if (fcntl(dupfd, F_GETFL, 0) >= 0)
 725                         continue;
 726                 if (dup2(nullfd, dupfd) == -1) {
 727                         fprintf(stderr, "dup2: %s\n", strerror(errno));
 728                         exit(1);
 729                 }
 730         }
 731         if (nullfd > 2)
 732                 close(nullfd);
 733 }
 734
 735 char *
 736 tohex(const void *vp, size_t l)
 737 {
 738         const u_char *p = (const u_char *)vp;
 739         char b[3], *r;
 740         size_t i, hl;
 741
 742         if (l > 65536)
 743                 return xstrdup("tohex: length > 65536");
 744
 745         hl = l * 2 + 1;
 746         r = xcalloc(1, hl);
 747         for (i = 0; i < l; i++) {
 748                 snprintf(b, sizeof(b), "%02x", p[i]);
 749                 strlcat(r, b, hl);
 750         }
 751         return (r);
 752 }
 753
 754 u_int64_t
 755 get_u64(const void *vp)
 756 {
 757         const u_char *p = (const u_char *)vp;
 758         u_int64_t v;
 759
 760         v  = (u_int64_t)p[0] << 56;
 761         v |= (u_int64_t)p[1] << 48;
 762         v |= (u_int64_t)p[2] << 40;
 763         v |= (u_int64_t)p[3] << 32;
 764         v |= (u_int64_t)p[4] << 24;
 765         v |= (u_int64_t)p[5] << 16;
 766         v |= (u_int64_t)p[6] << 8;
 767         v |= (u_int64_t)p[7];
 768
 769         return (v);
 770 }
 771
 772 u_int32_t
 773 get_u32(const void *vp)
 774 {
 775         const u_char *p = (const u_char *)vp;
 776         u_int32_t v;
 777
 778         v  = (u_int32_t)p[0] << 24;
 779         v |= (u_int32_t)p[1] << 16;
 780         v |= (u_int32_t)p[2] << 8;
 781         v |= (u_int32_t)p[3];
 782
 783         return (v);
 784 }
 785
 786 u_int16_t
 787 get_u16(const void *vp)
 788 {
 789         const u_char *p = (const u_char *)vp;
 790         u_int16_t v;
 791
 792         v  = (u_int16_t)p[0] << 8;
 793         v |= (u_int16_t)p[1];
 794
 795         return (v);
 796 }
 797
 798 void
 799 put_u64(void *vp, u_int64_t v)
 800 {
 801         u_char *p = (u_char *)vp;
 802
 803         p[0] = (u_char)(v >> 56) & 0xff;
 804         p[1] = (u_char)(v >> 48) & 0xff;
 805         p[2] = (u_char)(v >> 40) & 0xff;
 806         p[3] = (u_char)(v >> 32) & 0xff;
 807         p[4] = (u_char)(v >> 24) & 0xff;
 808         p[5] = (u_char)(v >> 16) & 0xff;
 809         p[6] = (u_char)(v >> 8) & 0xff;
 810         p[7] = (u_char)v & 0xff;
 811 }
 812
 813 void
 814 put_u32(void *vp, u_int32_t v)
 815 {
 816         u_char *p = (u_char *)vp;
 817
 818         p[0] = (u_char)(v >> 24) & 0xff;
 819         p[1] = (u_char)(v >> 16) & 0xff;
 820         p[2] = (u_char)(v >> 8) & 0xff;
 821         p[3] = (u_char)v & 0xff;
 822 }
 823
 824
 825 void
 826 put_u16(void *vp, u_int16_t v)
 827 {
 828         u_char *p = (u_char *)vp;
 829
 830         p[0] = (u_char)(v >> 8) & 0xff;
 831         p[1] = (u_char)v & 0xff;
 832 }
 833
 834 void
 835 ms_subtract_diff(struct timeval *start, int *ms)
 836 {
 837         struct timeval diff, finish;
 838
 839         gettimeofday(&finish, NULL);
 840         timersub(&finish, start, &diff);
 841         *ms -= (diff.tv_sec * 1000) + (diff.tv_usec / 1000);
 842 }
 843
 844 void
 845 ms_to_timeval(struct timeval *tv, int ms)
 846 {
 847         if (ms < 0)
 848                 ms = 0;
 849         tv->tv_sec = ms / 1000;
 850         tv->tv_usec = (ms % 1000) * 1000;
 851 }
 852
 853 void
 854 bandwidth_limit_init(struct bwlimit *bw, u_int64_t kbps, size_t buflen)
 855 {
 856         bw->buflen = buflen;
 857         bw->rate = kbps;
 858         bw->thresh = bw->rate;
 859         bw->lamt = 0;
 860         timerclear(&bw->bwstart);
 861         timerclear(&bw->bwend);
 862 }
 863
 864 /* Callback from read/write loop to insert bandwidth-limiting delays */
 865 void
 866 bandwidth_limit(struct bwlimit *bw, size_t read_len)
 867 {
 868         u_int64_t waitlen;
 869         struct timespec ts, rm;
 870
 871         if (!timerisset(&bw->bwstart)) {
 872                 gettimeofday(&bw->bwstart, NULL);
 873                 return;
 874         }
 875
 876         bw->lamt += read_len;
 877         if (bw->lamt < bw->thresh)
 878                 return;
 879
 880         gettimeofday(&bw->bwend, NULL);
 881         timersub(&bw->bwend, &bw->bwstart, &bw->bwend);
 882         if (!timerisset(&bw->bwend))
 883                 return;
 884
 885         bw->lamt *= 8;
 886         waitlen = (double)1000000L * bw->lamt / bw->rate;
 887
 888         bw->bwstart.tv_sec = waitlen / 1000000L;
 889         bw->bwstart.tv_usec = waitlen % 1000000L;
 890
 891         if (timercmp(&bw->bwstart, &bw->bwend, >)) {
 892                 timersub(&bw->bwstart, &bw->bwend, &bw->bwend);
 893
 894                 /* Adjust the wait time */
 895                 if (bw->bwend.tv_sec) {
 896                         bw->thresh /= 2;
 897                         if (bw->thresh < bw->buflen / 4)
 898                                 bw->thresh = bw->buflen / 4;
 899                 } else if (bw->bwend.tv_usec < 10000) {
 900                         bw->thresh *= 2;
 901                         if (bw->thresh > bw->buflen * 8)
 902                                 bw->thresh = bw->buflen * 8;
 903                 }
 904
 905                 TIMEVAL_TO_TIMESPEC(&bw->bwend, &ts);
 906                 while (nanosleep(&ts, &rm) == -1) {
 907                         if (errno != EINTR)
 908                                 break;
 909                         ts = rm;
 910                 }
 911         }
 912
 913         bw->lamt = 0;
 914         gettimeofday(&bw->bwstart, NULL);
 915 }
 916 void
 917 sock_set_v6only(int s)
 918 {
 919 #ifdef IPV6_V6ONLY
 920         int on = 1;
 921
 922         debug3("%s: set socket %d IPV6_V6ONLY", __func__, s);
 923         if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) == -1)
 924                 error("setsockopt IPV6_V6ONLY: %s", strerror(errno));
 925 #endif
 926 }