| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: fw.c,v 1.2 1999/07/03 13:55:17 mdw Exp $ |
| 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 $ |
| 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. |
| 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" |
| 63 | #include "fw.h" |
| 64 | #include "listener.h" |
| 65 | #include "scan.h" |
| 66 | |
| 67 | /*----- Global variables --------------------------------------------------*/ |
| 68 | |
| 69 | sel_state *sel; /* Multiplexor for nonblocking I/O */ |
| 70 | unsigned flags = 0; /* Global state flags */ |
| 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 | { |
| 83 | fprintf(stderr, "Usage: %s [-db] [-f file] [config statements...]\n", |
| 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\ |
| 101 | -b, --background Fork into background after initializing.\n\ |
| 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\ |
| 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\ |
| 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); |
| 259 | chdir("/"); |
| 260 | setsid(); |
| 261 | |
| 262 | kid = fork(); |
| 263 | if (kid != 0) |
| 264 | _exit(0); |
| 265 | |
| 266 | flags |= FW_SYSLOG; |
| 267 | openlog(QUIS, 0, LOG_DAEMON); |
| 268 | } |
| 269 | |
| 270 | /* --- Let rip --- */ |
| 271 | |
| 272 | for (;;) |
| 273 | sel_select(sel); |
| 274 | return (0); |
| 275 | } |
| 276 | |
| 277 | /*----- That's all, folks -------------------------------------------------*/ |