1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574
|
/*
hts.c
Copyright (C) 1999, 2000 Lars Brinkhoff. See COPYING for terms and conditions.
hts is the server half of httptunnel. httptunnel creates a virtual
two-way data path tunneled in HTTP requests.
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd_.h>
#include <signal.h>
#include <sys/poll_.h>
#include <sys/time.h>
#include <sys/types.h>
#include <pwd.h>
#include <grp.h>
#include <time.h>
#include "common.h"
typedef struct
{
char *me;
char *device;
const char *host;
int port;
char *forward_host;
int forward_port;
size_t content_length;
char *pid_filename;
int use_std;
int use_daemon;
int strict_content_length;
int keep_alive;
int max_connection_age;
char *root;
char *user;
} Arguments;
int debug_level = 0;
FILE *debug_file = NULL;
static void
usage (FILE *f, const char *me)
{
fprintf (f,
"Usage: %s [OPTION]... [HOST:][PORT]\n"
"Listen for incoming httptunnel connections at PORT (default port is %d).\n"
"When a connection is made, I/O is redirected to the destination specified\n"
"by the --device, --forward-port or --stdin-stdout switch.\n"
"\n"
" -c, --content-length BYTES use HTTP PUT requests of BYTES size\n"
" (k, M, and G postfixes recognized)\n"
" -d, --device DEVICE use DEVICE for input and output\n"
#ifdef DEBUG_MODE
" -D, --debug [LEVEL] enable debug mode\n"
#endif
" -F, --forward-port HOST:PORT connect to PORT at HOST and use it for \n"
" input and output\n"
" -h, --help display this help and exit\n"
" -k, --keep-alive SECONDS send keepalive bytes every SECONDS seconds\n"
" (default is %d)\n"
#ifdef DEBUG_MODE
" -l, --logfile FILE specify logfile for debug output\n"
#endif
" -M, --max-connection-age SEC maximum time a connection will stay\n"
" open is SEC seconds (default is %d)\n"
" -r, --chroot ROOT change root to ROOT\n"
" -s, --stdin-stdout use stdin/stdout for communication\n"
" (implies --no-daemon)\n"
" -S, --strict-content-length always write Content-Length bytes in requests\n"
" -u, --user USER change user to USER\n"
" -V, --version output version information and exit\n"
" -w, --no-daemon don't fork into the background\n"
" -p, --pid-file LOCATION write a PID file to LOCATION\n"
"\n"
"Report bugs to %s.\n",
me, DEFAULT_HOST_PORT, DEFAULT_KEEP_ALIVE,
DEFAULT_MAX_CONNECTION_AGE, BUG_REPORT_EMAIL);
}
static void
parse_arguments (int argc, char **argv, Arguments *arg)
{
int c;
/* defaults */
arg->me = argv[0];
arg->host = NULL;
arg->port = DEFAULT_HOST_PORT;
arg->device = NULL;
arg->forward_host = NULL;
arg->forward_port = -1;
arg->content_length = DEFAULT_CONTENT_LENGTH;
arg->pid_filename = NULL;
arg->use_std = FALSE;
arg->use_daemon = TRUE;
arg->strict_content_length = FALSE;
arg->keep_alive = DEFAULT_KEEP_ALIVE;
arg->max_connection_age = DEFAULT_CONNECTION_MAX_TIME;
arg->user = NULL;
arg->root = NULL;
for (;;)
{
int option_index = 0;
static struct option long_options[] =
{
{ "help", no_argument, 0, 'h' },
{ "version", no_argument, 0, 'V' },
{ "no-daemon", no_argument, 0, 'w' },
{ "user", required_argument, 0, 'u' },
#ifdef DEBUG_MODE
{ "debug", required_argument, 0, 'D' },
{ "logfile", required_argument, 0, 'l' },
#endif
{ "chroot", required_argument, 0, 'r' },
{ "stdin-stdout", no_argument, 0, 's' },
{ "device", required_argument, 0, 'd' },
{ "pid-file", required_argument, 0, 'p' },
{ "keep-alive", required_argument, 0, 'k' },
{ "forward-port", required_argument, 0, 'F' },
{ "content-length", required_argument, 0, 'c' },
{ "strict-content-length", no_argument, 0, 'S' },
{ "max-connection-age", required_argument, 0, 'M' },
{ 0, 0, 0, 0 }
};
static const char *short_options = "c:d:F:hk:M:p:sSVwu:r:"
#ifdef DEBUG_MODE
"D:l:"
#endif
;
c = getopt_long (argc, argv, short_options,
long_options, &option_index);
if (c == -1)
break;
switch (c)
{
case 0:
fprintf (stderr, "option %s", long_options[option_index].name);
if (optarg)
fprintf (stderr, " with arg %s", optarg);
fprintf (stderr, "\n");
break;
case 'c':
arg->content_length = atoi_with_postfix (optarg);
break;
case 'd':
arg->device = optarg;
break;
#ifdef DEBUG_MODE
case 'D':
if (optarg)
debug_level = atoi (optarg);
else
debug_level = 1;
break;
case 'l':
debug_file = fopen (optarg, "w");
if (debug_file == NULL)
{
fprintf (stderr, "%s: couldn't open file %s for writing\n",
arg->me, optarg);
log_exit (1);
}
break;
#endif /* DEBUG_MODE */
case 'F':
name_and_port (optarg, &arg->forward_host, &arg->forward_port);
if (arg->forward_port == -1)
{
fprintf (stderr, "%s: you must specify a port number.\n"
"%s: try '%s --help' for help.\n",
arg->me, arg->me, arg->me);
exit (1);
}
break;
case 'h':
usage (stdout, arg->me);
exit (0);
case 'k':
arg->keep_alive = atoi (optarg);
break;
case 'M':
arg->max_connection_age = atoi (optarg);
break;
case 'r':
arg->root = optarg;
break;
case 's':
arg->use_std=TRUE;
arg->use_daemon=FALSE;
break;
case 'S':
arg->strict_content_length = TRUE;
break;
case 'u':
arg->user = optarg;
break;
case 'V':
printf ("hts (%s) %s\n", PACKAGE, VERSION);
exit (0);
case 'p':
arg->pid_filename = optarg;
break;
case 'w':
arg->use_daemon = FALSE;
break;
case '?':
break;
default:
fprintf (stderr, "?? getopt returned character code 0%o ??\n", c);
}
}
if (argc - 1 == optind)
{
char *colon = strchr (argv[optind], ':');
if (colon)
{
*colon = '\0';
arg->host = argv[optind];
arg->port = atoi (colon + 1);
}
else
arg->port = atoi (argv[optind]);
}
else if (argc - 1 > optind)
{
usage (stderr, arg->me);
exit (1);
}
if (arg->device == NULL && arg->forward_port == -1 && !arg->use_std)
{
fprintf (stderr, "%s: one of --device, --forward-port or --stdin-stdout must be used.\n"
"%s: try '%s -help' for help.\n",
arg->me, arg->me, arg->me);
exit (1);
}
if ((arg->device != NULL && arg->forward_port != -1) ||
(arg->device != NULL && arg->use_std) ||
(arg->forward_port != -1 && arg->use_std))
{
fprintf (stderr, "%s: only one of --device, --forward-port or --stdin-stdout can be used.\n"
"%s: try '%s --help' for help.\n",
arg->me, arg->me, arg->me);
exit (1);
}
if (debug_level == 0 && debug_file != NULL)
{
fprintf (stderr, "%s: --logfile can't be used without debugging\n",
arg->me);
exit (1);
}
/* Removed test ((arg->device == NULL) == (arg->forward_port == -1))
* by Sampo Niskanen - those have been tested already! */
if (arg->port == -1 ||
((arg->forward_host == NULL) != (arg->forward_port == -1)))
{
usage (stderr, arg->me);
exit (1);
}
}
int
main (int argc, char **argv)
{
int closed;
int fd = -1;
Arguments arg;
Tunnel *tunnel;
FILE *pid_file;
uid_t uid;
gid_t gid;
parse_arguments (argc, argv, &arg);
if ((debug_level == 0 || debug_file != NULL) && arg.use_daemon)
daemon (0, 1);
#ifdef DEBUG_MODE
if (debug_level != 0 && debug_file == NULL)
debug_file = stderr;
#else
openlog ("hts", LOG_PID, LOG_DAEMON);
#endif
log_notice ("hts (%s) %s started with arguments:", PACKAGE, VERSION);
log_notice (" me = %s", arg.me);
log_notice (" device = %s", arg.device ? arg.device : "(null)");
if (arg.host)
log_notice (" port = %s:%d", arg.host, arg.port);
else
log_notice (" port = %d", arg.port);
log_notice (" forward_port = %d", arg.forward_port);
log_notice (" forward_host = %s",
arg.forward_host ? arg.forward_host : "(null)");
log_notice (" content_length = %d", arg.content_length);
log_notice (" strict_content_length = %d", arg.strict_content_length);
log_notice (" use_std = %d", arg.use_std);
log_notice (" debug_level = %d", debug_level);
log_notice (" pid_filename = %s",
arg.pid_filename ? arg.pid_filename : "(null)");
log_notice (" chroot = %s", arg.root ? arg.root : "(null)");
log_notice (" user = %s", arg.user ? arg.user : "(null)");
tunnel = tunnel_new_server (arg.host, arg.port, arg.content_length);
if (tunnel == NULL)
{
log_error ("couldn't create tunnel");
log_exit (1);
}
if (tunnel_setopt (tunnel, "strict_content_length",
&arg.strict_content_length) == -1)
log_debug ("tunnel_setopt strict_content_length error: %s",
strerror (errno));
if (tunnel_setopt (tunnel, "keep_alive",
&arg.keep_alive) == -1)
log_debug ("tunnel_setopt keep_alive error: %s", strerror (errno));
if (tunnel_setopt (tunnel, "max_connection_age",
&arg.max_connection_age) == -1)
log_debug ("tunnel_setopt max_connection_age error: %s", strerror (errno));
#ifdef DEBUG_MODE
signal (SIGPIPE, log_sigpipe);
#else
signal (SIGPIPE, SIG_IGN);
#endif
if (arg.pid_filename != NULL)
{
pid_file = fopen (arg.pid_filename, "w+");
if (pid_file == NULL)
{
fprintf (stderr, "Couldn't open pid file %s: %s\n",
arg.pid_filename, strerror (errno));
}
else
{
fprintf (pid_file, "%d\n", (int)getpid ());
if (fclose (pid_file))
{
fprintf (stderr, "Error closing pid file: %s\n",
strerror (errno));
}
}
}
/* If requested to change user, get new uid and gid before chroot so we */
/* don't need /etc/passwd & company in the chroot jail */
if (arg.user)
{
struct passwd *pwd = getpwnam (arg.user);
if (pwd == NULL)
{
log_error ("couldn't find user");
log_exit (1);
}
uid = pwd->pw_uid;
gid = pwd->pw_gid;
if (setgroups (0, (const gid_t *)0) < 0)
{
log_error ("couldn't drop supplementary groups privileges");
log_exit (1);
}
if (setgid (gid) < 0)
{
log_error ("couldn't change primary group");
log_exit (1);
}
if (initgroups (arg.user, gid) < 0)
{
/* non critical error */
log_error ("couldn't add supplementary groups");
}
}
/* Change root if requested */
if (arg.root)
{
if (chroot (arg.root) < 0)
{
log_error ("couldn't change root");
log_exit (1);
}
if (chdir ("/") < 0)
{
log_error ("couldn't change dir to new root");
log_exit (1);
}
if (fclose (stdin) || fclose (stdout) || fclose (stderr))
{
log_error ("couldn't close stdin, stdout and/or stderr");
log_exit (1);
}
}
/* Change user if requested */
if (arg.user)
{
if (setuid (uid) < 0)
{
log_error ("couldn't change user");
log_exit (1);
}
}
for (;;)
{
time_t last_tunnel_write;
log_debug ("waiting for tunnel connection");
if (arg.device != NULL)
{
fd = open_device (arg.device);
log_debug ("open_device (\"%s\") = %d", arg.device, fd);
if (fd == -1)
{
log_error ("couldn't open %s: %s",
arg.device, strerror (errno));
log_exit (1);
}
/* Check that fd is not 0 (clash with --stdin-stdout) */
if (fd == 0)
{
log_notice("changing fd from %d to 3",fd);
if (dup2(fd,3) != 3)
{
log_error ("couldn't dup2(%d,3): %s",fd,strerror(errno));
log_exit (1);
}
}
} else if (arg.use_std) {
log_debug ("using stdin as fd");
fd = 0;
if (fcntl(fd,F_SETFL,O_NONBLOCK)==-1)
{
log_error ("couldn't set stdin to non-blocking mode: %s",
strerror(errno));
log_exit (1);
}
/* Usage of stdout (fd = 1) is checked later. */
}
if (tunnel_accept (tunnel) == -1)
{
log_notice ("couldn't accept connection: %s", strerror (errno));
continue;
}
if (arg.forward_port != -1)
{
struct sockaddr_in addr;
if (set_address (&addr, arg.forward_host, arg.forward_port) == -1)
{
log_error ("couldn't forward port to %s:%d: %s\n",
arg.forward_host, arg.forward_port, strerror (errno));
log_exit (1);
}
fd = do_connect (&addr);
log_debug ("do_connect (\"%s:%d\") = %d",
arg.forward_host, arg.forward_port, fd);
if (fd == -1)
{
log_error ("couldn't connect to %s:%d: %s\n",
arg.forward_host, arg.forward_port, strerror (errno));
log_exit (1);
}
/* Check that fd is not 0 (clash with --stdin-stdout) */
if (fd == 0)
{
log_notice("changing fd from %d to 3",fd);
if (dup2(fd,3) != 3)
{
log_error ("couldn't dup2(%d,3): %s",fd,strerror(errno));
log_exit (1);
}
}
}
closed = FALSE;
time (&last_tunnel_write);
while (!closed)
{
struct pollfd pollfd[2];
int timeout;
time_t t;
int n;
pollfd[0].fd = fd;
pollfd[0].events = POLLIN;
pollfd[1].fd = tunnel_pollin_fd (tunnel);
pollfd[1].events = POLLIN;
time (&t);
timeout = 1000 * (arg.keep_alive - (t - last_tunnel_write));
if (timeout < 0)
timeout = 0;
log_annoying ("poll () ...");
n = poll (pollfd, 2, timeout);
log_annoying ("... = %d", n);
if (n == -1)
{
log_error ("poll error: %s\n", strerror (errno));
log_exit (1);
}
else if (n == 0)
{
log_verbose ("poll() timed out");
tunnel_padding (tunnel, 1);
time (&last_tunnel_write);
continue;
}
log_annoying ("revents[0] = %x, revents[1] = %x, POLLIN = %x",
pollfd[0].revents, pollfd[1].revents, POLLIN);
handle_input ("device or port", tunnel, fd, pollfd[0].revents,
handle_device_input, &closed);
handle_input ("tunnel", tunnel, fd, pollfd[1].revents,
handle_tunnel_input, &closed);
if (pollfd[0].revents & POLLIN)
time (&last_tunnel_write);
}
log_debug ("closing tunnel");
if (fd != 0)
{
close (fd);
}
tunnel_close (tunnel);
log_notice ("disconnected from FIXME:hostname:port");
}
log_debug ("destroying tunnel");
tunnel_destroy (tunnel);
log_exit (0);
}
|