| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: fw.c,v 1.3 1999/07/26 23:30:42 mdw Exp $ |
| 4 | * |
| 5 | * Port forwarding thingy |
| 6 | * |
| 7 | * (c) 1999 Straylight/Edgeware |
| 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 $ |
| 32 | * Revision 1.3 1999/07/26 23:30:42 mdw |
| 33 | * Major reconstruction work for new design. |
| 34 | * |
| 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. |
| 41 | * |
| 42 | */ |
| 43 | |
| 44 | /*----- Header files ------------------------------------------------------*/ |
| 45 | |
| 46 | #include "config.h" |
| 47 | |
| 48 | #include <ctype.h> |
| 49 | #include <errno.h> |
| 50 | #include <signal.h> |
| 51 | #include <stdarg.h> |
| 52 | #include <stdio.h> |
| 53 | #include <stdlib.h> |
| 54 | #include <string.h> |
| 55 | #include <time.h> |
| 56 | |
| 57 | #include <unistd.h> |
| 58 | #include <syslog.h> |
| 59 | |
| 60 | #include <mLib/dstr.h> |
| 61 | #include <mLib/mdwopt.h> |
| 62 | #include <mLib/quis.h> |
| 63 | #include <mLib/report.h> |
| 64 | #include <mLib/sel.h> |
| 65 | #include <mLib/sig.h> |
| 66 | #include <mLib/sub.h> |
| 67 | |
| 68 | #include "bres.h" |
| 69 | #include "conf.h" |
| 70 | #include "endpt.h" |
| 71 | #include "exec.h" |
| 72 | #include "fattr.h" |
| 73 | #include "fw.h" |
| 74 | #include "scan.h" |
| 75 | #include "source.h" |
| 76 | |
| 77 | /*----- Global variables --------------------------------------------------*/ |
| 78 | |
| 79 | sel_state *sel; /* Multiplexor for nonblocking I/O */ |
| 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 |
| 89 | |
| 90 | /*----- Main code ---------------------------------------------------------*/ |
| 91 | |
| 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 | |
| 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 | { |
| 189 | fprintf(stderr, "Usage: %s [-db] [-f file] [config statements...]\n", |
| 190 | QUIS); |
| 191 | } |
| 192 | |
| 193 | static void help(FILE *fp) |
| 194 | { |
| 195 | version(fp); |
| 196 | fputc('\n', fp); |
| 197 | usage(fp); |
| 198 | fputs("\n\ |
| 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\ |
| 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\ |
| 208 | -d, --daemon Fork into background after initializing.\n\ |
| 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\ |
| 216 | continue to the end of the line. Each command line argument is considered\n\ |
| 217 | to be a separate line.\n\ |
| 218 | \n\ |
| 219 | The syntax is too complicated to describe here. Read the manual.\n\ |
| 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; |
| 237 | sig s_term, s_int; |
| 238 | scanner sc; |
| 239 | |
| 240 | enum { |
| 241 | f_bogus = 1, |
| 242 | f_file = 2, |
| 243 | f_fork = 8 |
| 244 | }; |
| 245 | |
| 246 | /* --- Initialize things --- */ |
| 247 | |
| 248 | ego(argv[0]); |
| 249 | sel = &sst; |
| 250 | sel_init(sel); |
| 251 | sub_init(); |
| 252 | sig_init(sel); |
| 253 | bres_init(sel); |
| 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); |
| 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' }, |
| 278 | { "fork", 0, 0, 'd' }, |
| 279 | { "daemon", 0, 0, 'd' }, |
| 280 | { "quiet", 0, 0, 'q' }, |
| 281 | |
| 282 | /* --- Magic terminator --- */ |
| 283 | |
| 284 | { 0, 0, 0, 0 } |
| 285 | }; |
| 286 | int i = mdwopt(argc, argv, "+hvu f:d", opts, 0, 0, 0); |
| 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; |
| 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 | } |
| 312 | f |= f_file; |
| 313 | break; |
| 314 | case 'd': |
| 315 | f |= f_fork; |
| 316 | break; |
| 317 | case 'q': |
| 318 | flags |= FW_QUIET; |
| 319 | break; |
| 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 | |
| 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); |
| 343 | } |
| 344 | |
| 345 | /* --- Parse the configuration now gathered --- */ |
| 346 | |
| 347 | conf_parse(&sc); |
| 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); |
| 361 | chdir("/"); |
| 362 | setsid(); |
| 363 | |
| 364 | kid = fork(); |
| 365 | if (kid != 0) |
| 366 | _exit(0); |
| 367 | |
| 368 | flags |= FW_SYSLOG; |
| 369 | openlog(QUIS, 0, LOG_DAEMON); |
| 370 | } |
| 371 | |
| 372 | /* --- Let rip --- */ |
| 373 | |
| 374 | if (!(flags & FW_SET)) |
| 375 | moan("nothing to do!"); |
| 376 | signal(SIGPIPE, SIG_IGN); |
| 377 | while (active) |
| 378 | sel_select(sel); |
| 379 | return (0); |
| 380 | } |
| 381 | |
| 382 | /*----- That's all, folks -------------------------------------------------*/ |