[fwd] / fw.c

/* -*-c-*-
 *
 * $Id: fw.c,v 1.2 1999/07/03 13:55:17 mdw Exp $
 *
 * Port forwarding thingy
 *
 * (c) 1999 Mark Wooding
 */

/*----- Licensing notice --------------------------------------------------* 
 *
 * This file is part of the `fw' port forwarder.
 *
 * `fw' is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * `fw' is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with `fw'; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/*----- Revision history --------------------------------------------------* 
 *
 * $Log: fw.c,v $
 * Revision 1.2  1999/07/03 13:55:17  mdw
 * Various changes.  Add configuration grammar to help text.  Change to
 * root directory and open syslog when forking into background.
 *
 * Revision 1.1.1.1  1999/07/01 08:56:23  mdw
 * Initial revision.
 *
 */

/*----- Header files ------------------------------------------------------*/

#include "config.h"

#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <unistd.h>
#include <syslog.h>

#include <mLib/mdwopt.h>
#include <mLib/quis.h>
#include <mLib/report.h>
#include <mLib/sel.h>
#include <mLib/sub.h>

#include "acl.h"
#include "bres.h"
#include "conf.h"
#include "fw.h"
#include "listener.h"
#include "scan.h"

/*----- Global variables --------------------------------------------------*/

sel_state *sel;				/* Multiplexor for nonblocking I/O */
unsigned flags = 0;			/* Global state flags */

/*----- Main code ---------------------------------------------------------*/

/* --- Standard GNU help options --- */

static void version(FILE *fp)
{
  fprintf(fp, "%s version " VERSION "\n", QUIS);
}

static void usage(FILE *fp)
{
  fprintf(stderr, "Usage: %s [-db] [-f file] [config statements...]\n",
	  QUIS);
}

static void help(FILE *fp)
{
  version(fp);
  fputc('\n', fp);
  usage(fp);
  fputs("\n\
A fairly full-featured port-forwarder.  Options available are:\n\
\n\
-h, --help		Display this help message.\n\
-v, --version		Display the program's version number.\n\
-u, --usage		Display a terse usage summary.\n\
\n\
-f, --file=FILE		Read configuration from a file.\n\
-d, --dump		Dump the configuration to standard output.\n\
-b, --background	Fork into background after initializing.\n\
\n\
Configuration may be supplied in one or more configuration files, or on\n\
the command line (or both).  If no `-f' option is present, and no\n\
configuration is given on the command line, the standard input stream is\n\
read.\n\
\n\
Configuration is free-form.  Comments begin with a `#' character and\n\
continue to the end of the line.  Each command line argument is considered\n\
to be a separate line.  The syntax is as follows:\n\
\n\
config : stmt...\n\
stmt : fwd-stmt | acl-stmt\n\
fwd-stmt : `forward' [`port'] port [`to'] addr [`:'] port [fwd-attr] [`;']\n\
fwd-attr : `{' acl-stmt... `}'\n\
acl-stmt : (`allow' | `deny') [`from'] addr [`/' mask] [`;']\n\
", fp);
}

/* --- @main@ --- *
 *
 * Arguments:	@int argc@ = number of command line arguments
 *		@char *argv[]@ = vector of argument strings
 *
 * Returns:	---
 *
 * Use:		Simple port-forwarding server.
 */

int main(int argc, char *argv[])
{
  unsigned f = 0;
  sel_state sst;

  enum {
    f_bogus = 1,
    f_file = 2,
    f_dump = 4,
    f_fork = 8
  };

  /* --- Initialize things --- */

  ego(argv[0]);
  sel = &sst;
  sel_init(sel);
  sub_init();
  bres_init(sel);

  /* --- Parse command line options --- */

  for (;;) {
    static struct option opts[] = {

      /* --- Standard GNU help options --- */

      { "help", 	0,		0,	'h' },
      { "version",	0,		0,	'v' },
      { "usage",	0,		0,	'u' },

      /* --- Other useful arguments --- */

      { "file",		OPTF_ARGREQ,	0,	'f' },
      { "dump",		0,		0,	'd' },
      { "fork",		0,		0,	'b' },
      { "background",	0,		0,	'b' },

      /* --- Magic terminator --- */

      { 0,		0,		0,	0 }
    };
    int i = mdwopt(argc, argv, "hvu f:db", opts, 0, 0, 0);

    if (i < 0)
      break;
    switch (i) {
      case 'h':
	help(stdout);
	exit(0);
	break;
      case 'v':
	version(stdout);
	exit(0);
	break;
      case 'u':
	usage(stdout);
	exit(0);
	break;
      case 'f': {
	scan_filectx ctx;
	FILE *fp;
	if ((fp = fopen(optarg, "r")) == 0)
	  die(1, "couldn't open file `%s': %s", optarg, strerror(errno));
	scan_fileinit(&ctx, fp, optarg);
	conf_parse(&ctx);
	fclose(fp);
	f |= f_file;
      } break;
      case 'd':
	f |= f_dump;
	break;
      case 'b':
	f |= f_fork;
	break;
      default:
	f |= f_bogus;
	break;
    }
  }

  if (f & f_bogus) {
    usage(stderr);
    exit(1);
  }

  /* --- Deal with the remaining arguments --- */

  if (optind == argc) {
    if (f & f_file)
      /* Cool */;
    else if (isatty(STDIN_FILENO)) {
      moan("no configuration given and stdin is a terminal.");
      moan("type `%s --help' for usage information.", QUIS);
      exit(1);
    } else {
      scan_filectx ctx;
      scan_fileinit(&ctx, stdin, "<stdin>");
      conf_parse(&ctx);
    }
  } else {
    scan_argvctx ctx;
    scan_argvinit(&ctx, argv + optind);
    conf_parse(&ctx);
  }

  /* --- Dump out the state --- */

  if (f & f_dump) {
    sel_file *s;
    fputs("global acl:\n", stdout);
    acl_dump(0, stdout);
    for (s = sel->files; s; s = s->next)
      listener_dump((listener *)s, stdout);
    exit(0);
  }

  /* --- Fork into the background --- */

  if (f & f_fork) {
    pid_t kid;

    kid = fork();
    if (kid == -1)
      die(1, "couldn't fork: %s", strerror(errno));
    if (kid != 0)
      _exit(0);

    close(0); close(1); close(2);
    chdir("/");
    setsid();

    kid = fork();
    if (kid != 0)
      _exit(0);

    flags |= FW_SYSLOG;
    openlog(QUIS, 0, LOG_DAEMON);
  }

  /* --- Let rip --- */

  for (;;)
    sel_select(sel);
  return (0);
}

/*----- That's all, folks -------------------------------------------------*/
Commit	Line	Data
e82f7154	1	/* --c--
e82f7154	2	*
afd7451e	3	* $Id: fw.c,v 1.2 1999/07/03 13:55:17 mdw Exp $
e82f7154	4	*
	5	* Port forwarding thingy
	6	*
	7	* (c) 1999 Mark Wooding
	8	*/
	9
	10	/----- Licensing notice --------------------------------------------------
	11	*
	12	* This file is part of the `fw' port forwarder.
	13	*
	14	* `fw' is free software; you can redistribute it and/or modify
	15	* it under the terms of the GNU General Public License as published by
	16	* the Free Software Foundation; either version 2 of the License, or
	17	* (at your option) any later version.
	18	*
	19	* `fw' is distributed in the hope that it will be useful,
	20	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	21	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	22	* GNU General Public License for more details.
	23	*
	24	* You should have received a copy of the GNU General Public License
	25	* along with `fw'; if not, write to the Free Software Foundation,
	26	* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
	27	*/
	28
	29	/----- Revision history --------------------------------------------------
	30	*
	31	* $Log: fw.c,v $
afd7451e	32	* Revision 1.2 1999/07/03 13:55:17 mdw
	33	* Various changes. Add configuration grammar to help text. Change to
	34	* root directory and open syslog when forking into background.
	35	*
	36	* Revision 1.1.1.1 1999/07/01 08:56:23 mdw
	37	* Initial revision.
e82f7154	38	*
	39	*/
	40
	41	/----- Header files ------------------------------------------------------/
	42
	43	#include "config.h"
	44
	45	#include <ctype.h>
	46	#include <errno.h>
	47	#include <stdio.h>
	48	#include <stdlib.h>
	49	#include <string.h>
	50
	51	#include <unistd.h>
	52	#include <syslog.h>
	53
	54	#include <mLib/mdwopt.h>
	55	#include <mLib/quis.h>
	56	#include <mLib/report.h>
	57	#include <mLib/sel.h>
	58	#include <mLib/sub.h>
	59
	60	#include "acl.h"
	61	#include "bres.h"
	62	#include "conf.h"
afd7451e	63	#include "fw.h"
e82f7154	64	#include "listener.h"
	65	#include "scan.h"
	66
afd7451e	67	/----- Global variables --------------------------------------------------/
e82f7154	68
e82f7154	69	sel_state sel; / Multiplexor for nonblocking I/O */
afd7451e	70	unsigned flags = 0; /* Global state flags */
e82f7154	71
	72	/----- Main code ---------------------------------------------------------/
	73
	74	/* --- Standard GNU help options --- */
	75
	76	static void version(FILE *fp)
	77	{
	78	fprintf(fp, "%s version " VERSION "\n", QUIS);
	79	}
	80
	81	static void usage(FILE *fp)
	82	{
afd7451e	83	fprintf(stderr, "Usage: %s [-db] [-f file] [config statements...]\n",
e82f7154	84	QUIS);
	85	}
	86
	87	static void help(FILE *fp)
	88	{
	89	version(fp);
	90	fputc('\n', fp);
	91	usage(fp);
	92	fputs("\n\
	93	A fairly full-featured port-forwarder. Options available are:\n\
	94	\n\
	95	-h, --help Display this help message.\n\
	96	-v, --version Display the program's version number.\n\
	97	-u, --usage Display a terse usage summary.\n\
	98	\n\
	99	-f, --file=FILE Read configuration from a file.\n\
	100	-d, --dump Dump the configuration to standard output.\n\
afd7451e	101	-b, --background Fork into background after initializing.\n\
e82f7154	102	\n\
	103	Configuration may be supplied in one or more configuration files, or on\n\
	104	the command line (or both). If no `-f' option is present, and no\n\
	105	configuration is given on the command line, the standard input stream is\n\
	106	read.\n\
	107	\n\
	108	Configuration is free-form. Comments begin with a `#' character and\n\
afd7451e	109	continue to the end of the line. Each command line argument is considered\n\
	110	to be a separate line. The syntax is as follows:\n\
	111	\n\
	112	config : stmt...\n\
	113	stmt : fwd-stmt \| acl-stmt\n\
	114	fwd-stmt : `forward' [`port'] port [`to'] addr [`:'] port [fwd-attr] [`;']\n\
	115	fwd-attr : `{' acl-stmt... `}'\n\
	116	acl-stmt : (`allow' \| `deny') [`from'] addr [`/' mask] [`;']\n\
e82f7154	117	", fp);
	118	}
	119
	120	/* --- @main@ --- *
	121	*
	122	* Arguments: @int argc@ = number of command line arguments
	123	* @char *argv[]@ = vector of argument strings
	124	*
	125	* Returns: ---
	126	*
	127	* Use: Simple port-forwarding server.
	128	*/
	129
	130	int main(int argc, char *argv[])
	131	{
	132	unsigned f = 0;
	133	sel_state sst;
	134
	135	enum {
	136	f_bogus = 1,
	137	f_file = 2,
	138	f_dump = 4,
	139	f_fork = 8
	140	};
	141
	142	/* --- Initialize things --- */
	143
	144	ego(argv[0]);
	145	sel = &sst;
	146	sel_init(sel);
	147	sub_init();
	148	bres_init(sel);
	149
	150	/* --- Parse command line options --- */
	151
	152	for (;;) {
	153	static struct option opts[] = {
	154
	155	/* --- Standard GNU help options --- */
	156
	157	{ "help", 0, 0, 'h' },
	158	{ "version", 0, 0, 'v' },
	159	{ "usage", 0, 0, 'u' },
	160
	161	/* --- Other useful arguments --- */
	162
	163	{ "file", OPTF_ARGREQ, 0, 'f' },
	164	{ "dump", 0, 0, 'd' },
	165	{ "fork", 0, 0, 'b' },
	166	{ "background", 0, 0, 'b' },
	167
	168	/* --- Magic terminator --- */
	169
	170	{ 0, 0, 0, 0 }
	171	};
	172	int i = mdwopt(argc, argv, "hvu f:db", opts, 0, 0, 0);
	173
	174	if (i < 0)
	175	break;
	176	switch (i) {
	177	case 'h':
	178	help(stdout);
	179	exit(0);
	180	break;
181	case 'v':
182	version(stdout);
183	exit(0);
184	break;
185	case 'u':
186	usage(stdout);
187	exit(0);
188	break;
189	case 'f': {
190	scan_filectx ctx;
191	FILE *fp;
192	if ((fp = fopen(optarg, "r")) == 0)
193	die(1, "couldn't open file `%s': %s", optarg, strerror(errno));
194	scan_fileinit(&ctx, fp, optarg);
195	conf_parse(&ctx);
196	fclose(fp);
197	f \|= f_file;
198	} break;
199	case 'd':
200	f \|= f_dump;
201	break;
202	case 'b':
203	f \|= f_fork;
204	break;
205	default:
206	f \|= f_bogus;
207	break;
208	}
209	}
210
211	if (f & f_bogus) {
212	usage(stderr);
213	exit(1);
214	}
215
216	/* --- Deal with the remaining arguments --- */
217
218	if (optind == argc) {
219	if (f & f_file)
220	/* Cool */;
221	else if (isatty(STDIN_FILENO)) {
222	moan("no configuration given and stdin is a terminal.");
223	moan("type `%s --help' for usage information.", QUIS);
224	exit(1);
225	} else {
226	scan_filectx ctx;
227	scan_fileinit(&ctx, stdin, "<stdin>");
228	conf_parse(&ctx);
229	}
230	} else {
231	scan_argvctx ctx;
232	scan_argvinit(&ctx, argv + optind);
233	conf_parse(&ctx);
234	}
235
236	/* --- Dump out the state --- */
237
238	if (f & f_dump) {
239	sel_file *s;
240	fputs("global acl:\n", stdout);
241	acl_dump(0, stdout);
242	for (s = sel->files; s; s = s->next)
243	listener_dump((listener *)s, stdout);
244	exit(0);
245	}
246
247	/* --- Fork into the background --- */
248
249	if (f & f_fork) {
250	pid_t kid;
251
252	kid = fork();
253	if (kid == -1)
254	die(1, "couldn't fork: %s", strerror(errno));
255	if (kid != 0)
256	_exit(0);
257
258	close(0); close(1); close(2);
afd7451e	259	chdir("/");
e82f7154	260	setsid();
	261
	262	kid = fork();
	263	if (kid != 0)
	264	_exit(0);
afd7451e	265
	266	flags \|= FW_SYSLOG;
	267	openlog(QUIS, 0, LOG_DAEMON);
e82f7154	268	}
	269
	270	/* --- Let rip --- */
	271
e82f7154	272	for (;;)
	273	sel_select(sel);
	274	return (0);
	275	}
	276
	277	/----- That's all, folks -------------------------------------------------/