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