| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: conf.c,v 1.1 1999/07/01 08:56:23 mdw Exp $ |
| 4 | * |
| 5 | * Configuration parsing |
| 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: conf.c,v $ |
| 32 | * Revision 1.1 1999/07/01 08:56:23 mdw |
| 33 | * Initial revision |
| 34 | * |
| 35 | */ |
| 36 | |
| 37 | /*----- Header files ------------------------------------------------------*/ |
| 38 | |
| 39 | #include "config.h" |
| 40 | |
| 41 | #include <ctype.h> |
| 42 | #include <errno.h> |
| 43 | #include <stdarg.h> |
| 44 | #include <stdio.h> |
| 45 | #include <stdlib.h> |
| 46 | #include <string.h> |
| 47 | |
| 48 | #include <sys/socket.h> |
| 49 | #include <netinet/in.h> |
| 50 | #include <arpa/inet.h> |
| 51 | #include <netdb.h> |
| 52 | |
| 53 | #include <mLib/dstr.h> |
| 54 | #include <mLib/quis.h> |
| 55 | #include <mLib/report.h> |
| 56 | |
| 57 | #include "acl.h" |
| 58 | #include "listener.h" |
| 59 | #include "scan.h" |
| 60 | |
| 61 | /*----- Magic numbers -----------------------------------------------------*/ |
| 62 | |
| 63 | #define CTOK_EOF (-1) |
| 64 | #define CTOK_WORD 256 |
| 65 | |
| 66 | /*----- Main code ---------------------------------------------------------*/ |
| 67 | |
| 68 | /* --- @token@ --- * |
| 69 | * |
| 70 | * Arguments: @scanner *sc@ = pointer to scanner definition |
| 71 | * |
| 72 | * Returns: Type of token scanned. |
| 73 | * |
| 74 | * Use: Reads the next token from the character scanner. |
| 75 | */ |
| 76 | |
| 77 | static int token(scanner *sc) |
| 78 | { |
| 79 | #define SCAN(sc) (sc)->ops->scan((sc)) |
| 80 | #define UNSCAN(sc, x) (sc)->ops->unscan((x), (sc)) |
| 81 | |
| 82 | int ch; |
| 83 | |
| 84 | for (;;) { |
| 85 | ch = SCAN(sc); |
| 86 | if (ch == '\n') |
| 87 | sc->line++; |
| 88 | else if (isspace((unsigned char)ch)) |
| 89 | ; |
| 90 | else switch (ch) { |
| 91 | case EOF: |
| 92 | return (sc->t = CTOK_EOF); |
| 93 | case '#': |
| 94 | do ch = SCAN(sc); while (ch != EOF && ch != '\n'); |
| 95 | if (ch == '\n') |
| 96 | sc->line++; |
| 97 | break; |
| 98 | case '{': |
| 99 | case '}': |
| 100 | case ':': |
| 101 | case '/': |
| 102 | case ';': |
| 103 | return (sc->t = ch); |
| 104 | default: |
| 105 | DRESET(&sc->d); |
| 106 | do { |
| 107 | DPUTC(&sc->d, ch); |
| 108 | ch = SCAN(sc); |
| 109 | } while (ch != EOF && ch != '{' && ch != ';' && |
| 110 | ch != '}' && ch != ':' && ch != '/' && |
| 111 | !isspace((unsigned char)(ch))); |
| 112 | UNSCAN(sc, ch); |
| 113 | DPUTZ(&sc->d); |
| 114 | return (sc->t = CTOK_WORD); |
| 115 | } |
| 116 | } |
| 117 | |
| 118 | #undef SCAN |
| 119 | #undef UNSCAN |
| 120 | } |
| 121 | |
| 122 | /* --- @error@ --- * |
| 123 | * |
| 124 | * Arguments: @scanner *sc@ = pointer to scanner definition |
| 125 | * @const char *msg@ = message skeleton string |
| 126 | * @...@ = extra arguments for the skeleton |
| 127 | * |
| 128 | * Returns: Doesn't |
| 129 | * |
| 130 | * Use: Reports an error at the current scanner location. |
| 131 | */ |
| 132 | |
| 133 | static void error(scanner *sc, const char *msg, ...) |
| 134 | { |
| 135 | va_list ap; |
| 136 | va_start(ap, msg); |
| 137 | fprintf(stderr, "%s: %s:%i: ", QUIS, sc->src, sc->line); |
| 138 | vfprintf(stderr, msg, ap); |
| 139 | fputc('\n', stderr); |
| 140 | exit(1); |
| 141 | } |
| 142 | |
| 143 | /* --- @portnum@ --- * |
| 144 | * |
| 145 | * Arguments: @scanner *sc@ = pointer to scanner (for error reporting) |
| 146 | * @const char *p@ = pointer to port name |
| 147 | * |
| 148 | * Returns: Port number (network byte order) |
| 149 | * |
| 150 | * Use: Converts a textual port name or number into a usable thing. |
| 151 | */ |
| 152 | |
| 153 | static unsigned short portnum(scanner *sc, const char *p) |
| 154 | { |
| 155 | struct servent *s; |
| 156 | if (isdigit((unsigned char)*p)) |
| 157 | return (htons(atoi(p))); |
| 158 | if ((s = getservbyname(p, "tcp")) == 0) |
| 159 | error(sc, "unknown tcp service `%s'", p); |
| 160 | return (s->s_port); |
| 161 | } |
| 162 | |
| 163 | /* --- @getconf@ --- * |
| 164 | * |
| 165 | * Arguments: @scanner *sc@ = pointer to scanner to read from |
| 166 | * @listener *l@ = listener to configure (or zero) |
| 167 | * @acl_entry ***a@ = pointer to tail of ACL (or zero) |
| 168 | * |
| 169 | * Returns: --- |
| 170 | * |
| 171 | * Use: Reads a local or global configuration statement. |
| 172 | */ |
| 173 | |
| 174 | static void getconf(scanner *sc, listener *l, acl_entry ***a) |
| 175 | { |
| 176 | unsigned act; |
| 177 | |
| 178 | /* --- Access control limitations --- */ |
| 179 | |
| 180 | if ((strcmp(sc->d.buf, "allow") == 0 && (act = ACL_ALLOW, 1)) || |
| 181 | (strcmp(sc->d.buf, "deny") == 0 && (act = ACL_DENY, 1))) { |
| 182 | struct hostent *h; |
| 183 | struct netent *n; |
| 184 | struct in_addr addr, mask; |
| 185 | |
| 186 | /* --- Find the host or network address --- */ |
| 187 | |
| 188 | token(sc); |
| 189 | if (sc->t == CTOK_WORD && strcmp(sc->d.buf, "from") == 0) |
| 190 | token(sc); |
| 191 | if (sc->t != CTOK_WORD) |
| 192 | error(sc, "parse error, address expected"); |
| 193 | if ((n = getnetbyname(sc->d.buf)) != 0) |
| 194 | addr.s_addr = htonl(n->n_net); |
| 195 | else if ((h = gethostbyname(sc->d.buf)) == 0) |
| 196 | error(sc, "couldn't resolve address `%s'", sc->d.buf); |
| 197 | else |
| 198 | memcpy(&addr, h->h_addr, sizeof(struct in_addr)); |
| 199 | token(sc); |
| 200 | |
| 201 | /* --- Find the netmask, if any --- */ |
| 202 | |
| 203 | if (sc->t != '/') |
| 204 | mask.s_addr = ~0ul; |
| 205 | else { |
| 206 | token(sc); |
| 207 | if (sc->t != CTOK_WORD) |
| 208 | error(sc, "parse error, netmask expected"); |
| 209 | if (strchr(sc->d.buf, '.') == 0) |
| 210 | mask.s_addr = htonl((~0ul << (32 - atoi(sc->d.buf))) & 0xffffffff); |
| 211 | else { |
| 212 | #ifdef HAVE_INET_ATON |
| 213 | if (!inet_aton(sc->d.buf, &mask)) |
| 214 | error(sc, "bad netmask `%s'", sc->d.buf); |
| 215 | #else |
| 216 | mask.s_addr = inet_addr(sc->d.buf); |
| 217 | #endif |
| 218 | } |
| 219 | token(sc); |
| 220 | } |
| 221 | |
| 222 | /* --- Add the access control entry --- */ |
| 223 | |
| 224 | acl_add(a, act, addr, mask); |
| 225 | } |
| 226 | |
| 227 | /* --- Anything unrecognized --- */ |
| 228 | |
| 229 | else |
| 230 | error(sc, "parse error, unknown configuration keyword `%s'", sc->d.buf); |
| 231 | } |
| 232 | |
| 233 | /* --- @conf_parse@ --- * |
| 234 | * |
| 235 | * Arguments: @void *scp@ = pointer to scanner definition |
| 236 | * |
| 237 | * Returns: --- |
| 238 | * |
| 239 | * Use: Parses a configuration file from the scanner. |
| 240 | */ |
| 241 | |
| 242 | void conf_parse(void *scp) |
| 243 | { |
| 244 | scanner *sc = scp; |
| 245 | |
| 246 | token(sc); |
| 247 | |
| 248 | for (;;) { |
| 249 | if (sc->t == CTOK_EOF) |
| 250 | break; |
| 251 | if (sc->t != CTOK_WORD) |
| 252 | error(sc, "parse error, keyword expected"); |
| 253 | |
| 254 | /* --- Handle a forwarding request --- */ |
| 255 | |
| 256 | if (strcmp(sc->d.buf, "forward") == 0 || |
| 257 | strcmp(sc->d.buf, "fw") == 0) { |
| 258 | unsigned short sp, dp; |
| 259 | struct sockaddr_in sin; |
| 260 | struct hostent *h; |
| 261 | int fd; |
| 262 | listener *l; |
| 263 | |
| 264 | /* --- Read the source port --- */ |
| 265 | |
| 266 | token(sc); |
| 267 | if (sc->t == CTOK_WORD && strcmp(sc->d.buf, "port") == 0) |
| 268 | token(sc); |
| 269 | if (sc->t != CTOK_WORD) |
| 270 | error(sc, "parse error, source port expected"); |
| 271 | sp = portnum(sc, sc->d.buf); |
| 272 | |
| 273 | /* --- Read the destination address --- */ |
| 274 | |
| 275 | token(sc); |
| 276 | if (sc->t == CTOK_WORD && strcmp(sc->d.buf, "to") == 0) |
| 277 | token(sc); |
| 278 | if (sc->t != CTOK_WORD) |
| 279 | error(sc, "parse error, destination address expected"); |
| 280 | if ((h = gethostbyname(sc->d.buf)) == 0) |
| 281 | error(sc, "couldn't resolve address `%s'", sc->d.buf); |
| 282 | |
| 283 | token(sc); |
| 284 | if (sc->t == ':') |
| 285 | token(sc); |
| 286 | if (sc->t != CTOK_WORD) |
| 287 | error(sc, "parse error, destination port expected"); |
| 288 | dp = portnum(sc, sc->d.buf); |
| 289 | |
| 290 | /* --- Make the socket --- */ |
| 291 | |
| 292 | if ((fd = socket(PF_INET, SOCK_STREAM, 0)) < 0) |
| 293 | error(sc, "couldn't create socket: %s", strerror(errno)); |
| 294 | |
| 295 | /* --- Set it to allow address reuse --- */ |
| 296 | |
| 297 | { |
| 298 | int opt = 1; |
| 299 | setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)); |
| 300 | } |
| 301 | |
| 302 | /* --- Bind it to the right port --- */ |
| 303 | |
| 304 | sin.sin_family = AF_INET; |
| 305 | sin.sin_addr.s_addr = htonl(INADDR_ANY); |
| 306 | sin.sin_port = sp; |
| 307 | if (bind(fd, (struct sockaddr *)&sin, sizeof(sin))) { |
| 308 | error(sc, "couldn't bind to port %i: %s", |
| 309 | ntohs(sp), strerror(errno)); |
| 310 | } |
| 311 | |
| 312 | /* --- Set it to listen for connections --- */ |
| 313 | |
| 314 | if (listen(fd, 5)) |
| 315 | error(sc, "couldn't listen on socket: %s", strerror(errno)); |
| 316 | |
| 317 | /* --- Fill in a new listener --- */ |
| 318 | |
| 319 | memcpy(&sin.sin_addr, h->h_addr, sizeof(struct in_addr)); |
| 320 | sin.sin_port = dp; |
| 321 | l = listener_add(fd, sp, &sin); |
| 322 | |
| 323 | /* --- Snarf access controls and other attributes --- */ |
| 324 | |
| 325 | token(sc); |
| 326 | if (sc->t == '{') { |
| 327 | acl_entry **a = &l->acl; |
| 328 | token(sc); |
| 329 | while (sc->t != '}') { |
| 330 | if (sc->t != CTOK_WORD) |
| 331 | error(sc, "parse error, keyword or `}' expected"); |
| 332 | getconf(sc, l, &a); |
| 333 | if (sc->t == ';') |
| 334 | token(sc); |
| 335 | } |
| 336 | *a = 0; |
| 337 | token(sc); |
| 338 | } |
| 339 | } |
| 340 | |
| 341 | /* --- Other configuration is handled elsewhere --- */ |
| 342 | |
| 343 | else |
| 344 | getconf(sc, 0, 0); |
| 345 | |
| 346 | if (sc->t == ';') |
| 347 | token(sc); |
| 348 | } |
| 349 | } |
| 350 | |
| 351 | /*----- That's all, folks -------------------------------------------------*/ |