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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: fw.c,v 1.3 1999/07/26 23:30:42 mdw Exp $ |
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4 | * |
5 | * Port forwarding thingy |
6 | * |
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7 | * (c) 1999 Straylight/Edgeware |
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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 $ |
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32 | * Revision 1.3 1999/07/26 23:30:42 mdw |
33 | * Major reconstruction work for new design. |
34 | * |
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35 | * Revision 1.2 1999/07/03 13:55:17 mdw |
36 | * Various changes. Add configuration grammar to help text. Change to |
37 | * root directory and open syslog when forking into background. |
38 | * |
39 | * Revision 1.1.1.1 1999/07/01 08:56:23 mdw |
40 | * Initial revision. |
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41 | * |
42 | */ |
43 | |
44 | /*----- Header files ------------------------------------------------------*/ |
45 | |
46 | #include "config.h" |
47 | |
48 | #include <ctype.h> |
49 | #include <errno.h> |
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50 | #include <signal.h> |
51 | #include <stdarg.h> |
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52 | #include <stdio.h> |
53 | #include <stdlib.h> |
54 | #include <string.h> |
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55 | #include <time.h> |
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56 | |
57 | #include <unistd.h> |
58 | #include <syslog.h> |
59 | |
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60 | #include <mLib/dstr.h> |
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61 | #include <mLib/mdwopt.h> |
62 | #include <mLib/quis.h> |
63 | #include <mLib/report.h> |
64 | #include <mLib/sel.h> |
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65 | #include <mLib/sig.h> |
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66 | #include <mLib/sub.h> |
67 | |
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68 | #include "bres.h" |
69 | #include "conf.h" |
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70 | #include "endpt.h" |
71 | #include "exec.h" |
72 | #include "fattr.h" |
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73 | #include "fw.h" |
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74 | #include "scan.h" |
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75 | #include "source.h" |
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76 | |
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77 | /*----- Global variables --------------------------------------------------*/ |
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78 | |
79 | sel_state *sel; /* Multiplexor for nonblocking I/O */ |
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80 | |
81 | /*----- Static variables --------------------------------------------------*/ |
82 | |
83 | static unsigned flags = 0; /* Global state flags */ |
84 | static unsigned active = 0; /* Number of active things */ |
85 | |
86 | #define FW_SYSLOG 1u |
87 | #define FW_QUIET 2u |
88 | #define FW_SET 4u |
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89 | |
90 | /*----- Main code ---------------------------------------------------------*/ |
91 | |
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92 | /* --- @fw_log@ --- * |
93 | * |
94 | * Arguments: @time_t t@ = when the connection occurred or (@-1@) |
95 | * @const char *fmt@ = format string to fill in |
96 | * @...@ = other arguments |
97 | * |
98 | * Returns: --- |
99 | * |
100 | * Use: Logs a connection. |
101 | */ |
102 | |
103 | void fw_log(time_t t, const char *fmt, ...) |
104 | { |
105 | struct tm *tm; |
106 | dstr d = DSTR_INIT; |
107 | va_list ap; |
108 | |
109 | if (flags & FW_QUIET) |
110 | return; |
111 | |
112 | if (t == -1) |
113 | t = time(0); |
114 | tm = localtime(&t); |
115 | DENSURE(&d, 64); |
116 | d.len += strftime(d.buf, d.sz, "%Y-%m-%d %H:%M:%S", tm); |
117 | DPUTC(&d, ' '); |
118 | va_start(ap, fmt); |
119 | dstr_vputf(&d, fmt, ap); |
120 | va_end(ap); |
121 | if (flags & FW_SYSLOG) |
122 | syslog(LOG_NOTICE, "%s", d.buf); |
123 | else { |
124 | DPUTC(&d, '\n'); |
125 | dstr_write(&d, stderr); |
126 | } |
127 | DDESTROY(&d); |
128 | } |
129 | |
130 | /* --- @fw_inc@, @fw_dec@ --- * |
131 | * |
132 | * Arguments: --- |
133 | * |
134 | * Returns: --- |
135 | * |
136 | * Use: Increments or decrements the active thing count. `fw' won't |
137 | * quit while there are active things. |
138 | */ |
139 | |
140 | void fw_inc(void) { flags |= FW_SET; active++; } |
141 | void fw_dec(void) { if (active) active--; } |
142 | |
143 | /* --- @fw_exit@ --- * |
144 | * |
145 | * Arguments: --- |
146 | * |
147 | * Returns: --- |
148 | * |
149 | * Use: Exits when appropriate. |
150 | */ |
151 | |
152 | static void fw_exit(void) |
153 | { |
154 | endpt_killall(); |
155 | source_killall(); |
156 | } |
157 | |
158 | /* --- @fw_tidy@ --- * |
159 | * |
160 | * Arguments: @int n@ = signal number |
161 | * @void *p@ = an uninteresting argument |
162 | * |
163 | * Returns: --- |
164 | * |
165 | * Use: Handles various signals and causes a clean tidy-up. |
166 | */ |
167 | |
168 | static void fw_tidy(int n, void *p) |
169 | { |
170 | const char *sn = "unexpected signal (bug!)"; |
171 | if (n == SIGTERM) |
172 | sn = "SIGTERM"; |
173 | else if (n == SIGINT) |
174 | sn = "SIGINT"; |
175 | |
176 | fw_log(-1, "closing down on %s", sn); |
177 | fw_exit(); |
178 | } |
179 | |
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180 | /* --- Standard GNU help options --- */ |
181 | |
182 | static void version(FILE *fp) |
183 | { |
184 | fprintf(fp, "%s version " VERSION "\n", QUIS); |
185 | } |
186 | |
187 | static void usage(FILE *fp) |
188 | { |
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189 | fprintf(stderr, "Usage: %s [-db] [-f file] [config statements...]\n", |
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190 | QUIS); |
191 | } |
192 | |
193 | static void help(FILE *fp) |
194 | { |
195 | version(fp); |
196 | fputc('\n', fp); |
197 | usage(fp); |
198 | fputs("\n\ |
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199 | An excessively full-featured port-forwarder, which subsumes large chunks\n\ |
200 | of the functionality of inetd, netcat, and normal cat. Options available\n\ |
201 | are:\n\ |
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202 | \n\ |
203 | -h, --help Display this help message.\n\ |
204 | -v, --version Display the program's version number.\n\ |
205 | -u, --usage Display a terse usage summary.\n\ |
206 | \n\ |
207 | -f, --file=FILE Read configuration from a file.\n\ |
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208 | -d, --daemon Fork into background after initializing.\n\ |
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209 | \n\ |
210 | Configuration may be supplied in one or more configuration files, or on\n\ |
211 | the command line (or both). If no `-f' option is present, and no\n\ |
212 | configuration is given on the command line, the standard input stream is\n\ |
213 | read.\n\ |
214 | \n\ |
215 | Configuration is free-form. Comments begin with a `#' character and\n\ |
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216 | continue to the end of the line. Each command line argument is considered\n\ |
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217 | to be a separate line.\n\ |
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218 | \n\ |
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219 | The syntax is too complicated to describe here. Read the manual.\n\ |
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220 | ", fp); |
221 | } |
222 | |
223 | /* --- @main@ --- * |
224 | * |
225 | * Arguments: @int argc@ = number of command line arguments |
226 | * @char *argv[]@ = vector of argument strings |
227 | * |
228 | * Returns: --- |
229 | * |
230 | * Use: Simple port-forwarding server. |
231 | */ |
232 | |
233 | int main(int argc, char *argv[]) |
234 | { |
235 | unsigned f = 0; |
236 | sel_state sst; |
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237 | sig s_term, s_int; |
238 | scanner sc; |
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239 | |
240 | enum { |
241 | f_bogus = 1, |
242 | f_file = 2, |
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243 | f_fork = 8 |
244 | }; |
245 | |
246 | /* --- Initialize things --- */ |
247 | |
248 | ego(argv[0]); |
249 | sel = &sst; |
250 | sel_init(sel); |
251 | sub_init(); |
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252 | sig_init(sel); |
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253 | bres_init(sel); |
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254 | exec_init(); |
255 | fattr_init(&fattr_global); |
256 | scan_create(&sc); |
257 | |
258 | /* --- Set up some signal handlers --- */ |
259 | |
260 | sig_add(&s_term, SIGTERM, fw_tidy, 0); |
261 | sig_add(&s_int, SIGINT, fw_tidy, 0); |
262 | atexit(fw_exit); |
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263 | |
264 | /* --- Parse command line options --- */ |
265 | |
266 | for (;;) { |
267 | static struct option opts[] = { |
268 | |
269 | /* --- Standard GNU help options --- */ |
270 | |
271 | { "help", 0, 0, 'h' }, |
272 | { "version", 0, 0, 'v' }, |
273 | { "usage", 0, 0, 'u' }, |
274 | |
275 | /* --- Other useful arguments --- */ |
276 | |
277 | { "file", OPTF_ARGREQ, 0, 'f' }, |
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278 | { "fork", 0, 0, 'd' }, |
279 | { "daemon", 0, 0, 'd' }, |
280 | { "quiet", 0, 0, 'q' }, |
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281 | |
282 | /* --- Magic terminator --- */ |
283 | |
284 | { 0, 0, 0, 0 } |
285 | }; |
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286 | int i = mdwopt(argc, argv, "+hvu f:d", opts, 0, 0, 0); |
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287 | |
288 | if (i < 0) |
289 | break; |
290 | switch (i) { |
291 | case 'h': |
292 | help(stdout); |
293 | exit(0); |
294 | break; |
295 | case 'v': |
296 | version(stdout); |
297 | exit(0); |
298 | break; |
299 | case 'u': |
300 | usage(stdout); |
301 | exit(0); |
302 | break; |
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303 | case 'f': |
304 | if (strcmp(optarg, "-") == 0) |
305 | scan_add(&sc, scan_file(stdin, "<stdin>", SCF_NOCLOSE)); |
306 | else { |
307 | FILE *fp; |
308 | if ((fp = fopen(optarg, "r")) == 0) |
309 | die(1, "couldn't open file `%s': %s", optarg, strerror(errno)); |
310 | scan_add(&sc, scan_file(fp, optarg, 0)); |
311 | } |
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312 | f |= f_file; |
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313 | break; |
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314 | case 'd': |
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315 | f |= f_fork; |
316 | break; |
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317 | case 'q': |
318 | flags |= FW_QUIET; |
319 | break; |
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320 | default: |
321 | f |= f_bogus; |
322 | break; |
323 | } |
324 | } |
325 | |
326 | if (f & f_bogus) { |
327 | usage(stderr); |
328 | exit(1); |
329 | } |
330 | |
331 | /* --- Deal with the remaining arguments --- */ |
332 | |
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333 | if (optind < argc) |
334 | scan_add(&sc, scan_argv(argv + optind)); |
335 | else if (f & f_file) |
336 | /* Cool */; |
337 | else if (!isatty(STDIN_FILENO)) |
338 | scan_add(&sc, scan_file(stdin, "<stdin>", SCF_NOCLOSE)); |
339 | else { |
340 | moan("no configuration given and stdin is a terminal."); |
341 | moan("type `%s --help' for usage information.", QUIS); |
342 | exit(1); |
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343 | } |
344 | |
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345 | /* --- Parse the configuration now gathered --- */ |
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346 | |
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347 | conf_parse(&sc); |
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348 | |
349 | /* --- Fork into the background --- */ |
350 | |
351 | if (f & f_fork) { |
352 | pid_t kid; |
353 | |
354 | kid = fork(); |
355 | if (kid == -1) |
356 | die(1, "couldn't fork: %s", strerror(errno)); |
357 | if (kid != 0) |
358 | _exit(0); |
359 | |
360 | close(0); close(1); close(2); |
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361 | chdir("/"); |
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362 | setsid(); |
363 | |
364 | kid = fork(); |
365 | if (kid != 0) |
366 | _exit(0); |
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367 | |
368 | flags |= FW_SYSLOG; |
369 | openlog(QUIS, 0, LOG_DAEMON); |
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370 | } |
371 | |
372 | /* --- Let rip --- */ |
373 | |
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374 | if (!(flags & FW_SET)) |
375 | moan("nothing to do!"); |
376 | signal(SIGPIPE, SIG_IGN); |
377 | while (active) |
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378 | sel_select(sel); |
379 | return (0); |
380 | } |
381 | |
382 | /*----- That's all, folks -------------------------------------------------*/ |