1/* $OpenBSD: parse.c,v 1.11 2004/05/05 23:07:47 deraadt Exp $ */
2/* $FreeBSD: head/sbin/dhclient/parse.c 147077 2005-06-07 04:14:54Z brooks $ */
3
4/* Common parser code for dhcpd and dhclient. */
5
6/*
7 * Copyright (c) 1995, 1996, 1997, 1998 The Internet Software Consortium.
8 * All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 *
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of The Internet Software Consortium nor the names
20 * of its contributors may be used to endorse or promote products derived
21 * from this software without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
24 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
25 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
26 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
27 * DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
28 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
29 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
30 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
31 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
32 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
33 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
34 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 *
37 * This software has been written for the Internet Software Consortium
38 * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
39 * Enterprises. To learn more about the Internet Software Consortium,
40 * see ``http://www.vix.com/isc''. To learn more about Vixie
41 * Enterprises, see ``http://www.vix.com''.
42 */
43
44#include "dhcpd.h"
45#include "dhctoken.h"
46
47/* Skip to the semicolon ending the current statement. If we encounter
48 * braces, the matching closing brace terminates the statement. If we
49 * encounter a right brace but haven't encountered a left brace, return
50 * leaving the brace in the token buffer for the caller. If we see a
51 * semicolon and haven't seen a left brace, return. This lets us skip
52 * over:
53 *
54 * statement;
55 * statement foo bar { }
56 * statement foo bar { statement { } }
57 * statement}
58 *
59 * ...et cetera.
60 */
61void
62skip_to_semi(FILE *cfile)
63{
64 int brace_count = 0, token;
65 char *val;
66
67 do {
68 token = peek_token(&val, cfile);
69 if (token == RBRACE) {
70 if (brace_count) {
71 token = next_token(&val, cfile);
72 if (!--brace_count)
73 return;
74 } else
75 return;
76 } else if (token == LBRACE) {
77 brace_count++;
78 } else if (token == SEMI && !brace_count) {
79 token = next_token(&val, cfile);
80 return;
81 } else if (token == '\n') {
82 /*
83 * EOL only happens when parsing
84 * /etc/resolv.conf, and we treat it like a
85 * semicolon because the resolv.conf file is
86 * line-oriented.
87 */
88 token = next_token(&val, cfile);
89 return;
90 }
91 token = next_token(&val, cfile);
92 } while (token != EOF);
93}
94
95int
96parse_semi(FILE *cfile)
97{
98 int token;
99 char *val;
100
101 token = next_token(&val, cfile);
102 if (token != SEMI) {
103 parse_warn("semicolon expected.");
104 skip_to_semi(cfile);
105 return (0);
106 }
107 return (1);
108}
109
110/*
111 * string-parameter :== STRING SEMI
112 */
113char *
114parse_string(FILE *cfile)
115{
116 char *val, *s;
117 int token;
118
119 token = next_token(&val, cfile);
120 if (token != STRING) {
121 parse_warn("filename must be a string");
122 skip_to_semi(cfile);
123 return (NULL);
124 }
125 s = malloc(strlen(val) + 1);
126 if (!s)
127 error("no memory for string %s.", val);
128 strlcpy(s, val, strlen(val) + 1);
129
130 if (!parse_semi(cfile))
131 return (NULL);
132 return (s);
133}
134
135int
136parse_ip_addr(FILE *cfile, struct iaddr *addr)
137{
138 addr->len = 4;
139 if (parse_numeric_aggregate(cfile, addr->iabuf,
140 &addr->len, DOT, 10, 8))
141 return (1);
142 return (0);
143}
144
145/*
146 * hardware-parameter :== HARDWARE ETHERNET csns SEMI
147 * csns :== NUMBER | csns COLON NUMBER
148 */
149void
150parse_hardware_param(FILE *cfile, struct hardware *hardware)
151{
152 unsigned char *t;
153 int token, hlen;
154 char *val;
155
156 token = next_token(&val, cfile);
157 switch (token) {
158 case ETHERNET:
159 hardware->htype = HTYPE_ETHER;
160 break;
161 case TOKEN_RING:
162 hardware->htype = HTYPE_IEEE802;
163 break;
164 case FDDI:
165 hardware->htype = HTYPE_FDDI;
166 break;
167 default:
168 parse_warn("expecting a network hardware type");
169 skip_to_semi(cfile);
170 return;
171 }
172
173 /*
174 * Parse the hardware address information. Technically, it
175 * would make a lot of sense to restrict the length of the data
176 * we'll accept here to the length of a particular hardware
177 * address type. Unfortunately, there are some broken clients
178 * out there that put bogus data in the chaddr buffer, and we
179 * accept that data in the lease file rather than simply failing
180 * on such clients. Yuck.
181 */
182 hlen = 0;
183 t = parse_numeric_aggregate(cfile, NULL, &hlen, COLON, 16, 8);
184 if (!t)
185 return;
186 if (hlen > sizeof(hardware->haddr)) {
187 free(t);
188 parse_warn("hardware address too long");
189 } else {
190 hardware->hlen = hlen;
191 memcpy((unsigned char *)&hardware->haddr[0], t,
192 hardware->hlen);
193 if (hlen < sizeof(hardware->haddr))
194 memset(&hardware->haddr[hlen], 0,
195 sizeof(hardware->haddr) - hlen);
196 free(t);
197 }
198
199 token = next_token(&val, cfile);
200 if (token != SEMI) {
201 parse_warn("expecting semicolon.");
202 skip_to_semi(cfile);
203 }
204}
205
206/*
207 * lease-time :== NUMBER SEMI
208 */
209void
210parse_lease_time(FILE *cfile, time_t *timep)
211{
212 char *val;
213 int token;
214
215 token = next_token(&val, cfile);
216 if (token != NUMBER) {
217 parse_warn("Expecting numeric lease time");
218 skip_to_semi(cfile);
219 return;
220 }
221 convert_num((unsigned char *)timep, val, 10, 32);
222 /* Unswap the number - convert_num returns stuff in NBO. */
223 *timep = ntohl(*timep); /* XXX */
224
225 parse_semi(cfile);
226}
227
228/*
229 * No BNF for numeric aggregates - that's defined by the caller. What
230 * this function does is to parse a sequence of numbers separated by the
231 * token specified in separator. If max is zero, any number of numbers
232 * will be parsed; otherwise, exactly max numbers are expected. Base
233 * and size tell us how to internalize the numbers once they've been
234 * tokenized.
235 */
236unsigned char *
237parse_numeric_aggregate(FILE *cfile, unsigned char *buf, int *max,
238 int separator, int base, int size)
239{
240 unsigned char *bufp = buf, *s = NULL;
241 int token, count = 0;
242 char *val, *t;
243 pair c = NULL;
244
245 if (!bufp && *max) {
246 bufp = malloc(*max * size / 8);
247 if (!bufp)
248 error("can't allocate space for numeric aggregate");
249 } else
250 s = bufp;
251
252 do {
253 if (count) {
254 token = peek_token(&val, cfile);
255 if (token != separator) {
256 if (!*max)
257 break;
258 if (token != RBRACE && token != LBRACE)
259 token = next_token(&val, cfile);
260 parse_warn("too few numbers.");
261 if (token != SEMI)
262 skip_to_semi(cfile);
263 return (NULL);
264 }
265 token = next_token(&val, cfile);
266 }
267 token = next_token(&val, cfile);
268
269 if (token == EOF) {
270 parse_warn("unexpected end of file");
271 break;
272 }
273
274 /* Allow NUMBER_OR_NAME if base is 16. */
275 if (token != NUMBER &&
276 (base != 16 || token != NUMBER_OR_NAME)) {
277 parse_warn("expecting numeric value.");
278 skip_to_semi(cfile);
279 return (NULL);
280 }
281 /*
282 * If we can, convert the number now; otherwise, build a
283 * linked list of all the numbers.
284 */
285 if (s) {
286 convert_num(s, val, base, size);
287 s += size / 8;
288 } else {
289 t = malloc(strlen(val) + 1);
290 if (!t)
291 error("no temp space for number.");
292 strlcpy(t, val, strlen(val) + 1);
293 c = cons(t, c);
294 }
295 } while (++count != *max);
296
297 /* If we had to cons up a list, convert it now. */
298 if (c) {
299 bufp = malloc(count * size / 8);
300 if (!bufp)
301 error("can't allocate space for numeric aggregate.");
302 s = bufp + count - size / 8;
303 *max = count;
304 }
305 while (c) {
306 pair cdr = c->cdr;
307 convert_num(s, (char *)c->car, base, size);
308 s -= size / 8;
309 /* Free up temp space. */
310 free(c->car);
311 free(c);
312 c = cdr;
313 }
314 return (bufp);
315}
316
317void
318convert_num(unsigned char *buf, char *str, int base, int size)
319{
320 int negative = 0, tval, max;
321 u_int32_t val = 0;
322 char *ptr = str;
323
324 if (*ptr == '-') {
325 negative = 1;
326 ptr++;
327 }
328
329 /* If base wasn't specified, figure it out from the data. */
330 if (!base) {
331 if (ptr[0] == '0') {
332 if (ptr[1] == 'x') {
333 base = 16;
334 ptr += 2;
335 } else if (isascii(ptr[1]) && isdigit(ptr[1])) {
336 base = 8;
337 ptr += 1;
338 } else
339 base = 10;
340 } else
341 base = 10;
342 }
343
344 do {
345 tval = *ptr++;
346 /* XXX assumes ASCII... */
347 if (tval >= 'a')
348 tval = tval - 'a' + 10;
349 else if (tval >= 'A')
350 tval = tval - 'A' + 10;
351 else if (tval >= '0')
352 tval -= '0';
353 else {
354 warning("Bogus number: %s.", str);
355 break;
356 }
357 if (tval >= base) {
358 warning("Bogus number: %s: digit %d not in base %d",
359 str, tval, base);
360 break;
361 }
362 val = val * base + tval;
363 } while (*ptr);
364
365 if (negative)
366 max = (1 << (size - 1));
367 else
368 max = (1 << (size - 1)) + ((1 << (size - 1)) - 1);
369 if (val > max) {
370 switch (base) {
371 case 8:
372 warning("value %s%o exceeds max (%d) for precision.",
373 negative ? "-" : "", val, max);
374 break;
375 case 16:
376 warning("value %s%x exceeds max (%d) for precision.",
377 negative ? "-" : "", val, max);
378 break;
379 default:
380 warning("value %s%u exceeds max (%d) for precision.",
381 negative ? "-" : "", val, max);
382 break;
383 }
384 }
385
386 if (negative)
387 switch (size) {
388 case 8:
389 *buf = -(unsigned long)val;
390 break;
391 case 16:
392 putShort(buf, -(unsigned long)val);
393 break;
394 case 32:
395 putLong(buf, -(unsigned long)val);
396 break;
397 default:
398 warning("Unexpected integer size: %d", size);
399 break;
400 }
401 else
402 switch (size) {
403 case 8:
404 *buf = (u_int8_t)val;
405 break;
406 case 16:
407 putUShort(buf, (u_int16_t)val);
408 break;
409 case 32:
410 putULong(buf, val);
411 break;
412 default:
413 warning("Unexpected integer size: %d", size);
414 break;
415 }
416}
417
418/*
419 * date :== NUMBER NUMBER SLASH NUMBER SLASH NUMBER
420 * NUMBER COLON NUMBER COLON NUMBER SEMI
421 *
422 * Dates are always in GMT; first number is day of week; next is
423 * year/month/day; next is hours:minutes:seconds on a 24-hour
424 * clock.
425 */
426time_t
427parse_date(FILE *cfile)
428{
429 static int months[11] = { 31, 59, 90, 120, 151, 181,
430 212, 243, 273, 304, 334 };
431 int guess, token;
432 struct tm tm;
433 char *val;
434
435 /* Day of week... */
436 token = next_token(&val, cfile);
437 if (token != NUMBER) {
438 parse_warn("numeric day of week expected.");
439 if (token != SEMI)
440 skip_to_semi(cfile);
441 return (0);
442 }
443 tm.tm_wday = atoi(val);
444
445 /* Year... */
446 token = next_token(&val, cfile);
447 if (token != NUMBER) {
448 parse_warn("numeric year expected.");
449 if (token != SEMI)
450 skip_to_semi(cfile);
451 return (0);
452 }
453 tm.tm_year = atoi(val);
454 if (tm.tm_year > 1900)
455 tm.tm_year -= 1900;
456
457 /* Slash separating year from month... */
458 token = next_token(&val, cfile);
459 if (token != SLASH) {
460 parse_warn("expected slash separating year from month.");
461 if (token != SEMI)
462 skip_to_semi(cfile);
463 return (0);
464 }
465
466 /* Month... */
467 token = next_token(&val, cfile);
468 if (token != NUMBER) {
469 parse_warn("numeric month expected.");
470 if (token != SEMI)
471 skip_to_semi(cfile);
472 return (0);
473 }
474 tm.tm_mon = atoi(val) - 1;
475
476 /* Slash separating month from day... */
477 token = next_token(&val, cfile);
478 if (token != SLASH) {
479 parse_warn("expected slash separating month from day.");
480 if (token != SEMI)
481 skip_to_semi(cfile);
482 return (0);
483 }
484
485 /* Month... */
486 token = next_token(&val, cfile);
487 if (token != NUMBER) {
488 parse_warn("numeric day of month expected.");
489 if (token != SEMI)
490 skip_to_semi(cfile);
491 return (0);
492 }
493 tm.tm_mday = atoi(val);
494
495 /* Hour... */
496 token = next_token(&val, cfile);
497 if (token != NUMBER) {
498 parse_warn("numeric hour expected.");
499 if (token != SEMI)
500 skip_to_semi(cfile);
501 return (0);
502 }
503 tm.tm_hour = atoi(val);
504
505 /* Colon separating hour from minute... */
506 token = next_token(&val, cfile);
507 if (token != COLON) {
508 parse_warn("expected colon separating hour from minute.");
509 if (token != SEMI)
510 skip_to_semi(cfile);
511 return (0);
512 }
513
514 /* Minute... */
515 token = next_token(&val, cfile);
516 if (token != NUMBER) {
517 parse_warn("numeric minute expected.");
518 if (token != SEMI)
519 skip_to_semi(cfile);
520 return (0);
521 }
522 tm.tm_min = atoi(val);
523
524 /* Colon separating minute from second... */
525 token = next_token(&val, cfile);
526 if (token != COLON) {
527 parse_warn("expected colon separating hour from minute.");
528 if (token != SEMI)
529 skip_to_semi(cfile);
530 return (0);
531 }
532
533 /* Minute... */
534 token = next_token(&val, cfile);
535 if (token != NUMBER) {
536 parse_warn("numeric minute expected.");
537 if (token != SEMI)
538 skip_to_semi(cfile);
539 return (0);
540 }
541 tm.tm_sec = atoi(val);
542 tm.tm_isdst = 0;
543
544 /* XXX: We assume that mktime does not use tm_yday. */
545 tm.tm_yday = 0;
546
547 /* Make sure the date ends in a semicolon... */
548 token = next_token(&val, cfile);
549 if (token != SEMI) {
550 parse_warn("semicolon expected.");
551 skip_to_semi(cfile);
552 return (0);
553 }
554
555 /* Guess the time value... */
556 guess = ((((((365 * (tm.tm_year - 70) + /* Days in years since '70 */
557 (tm.tm_year - 69) / 4 + /* Leap days since '70 */
558 (tm.tm_mon /* Days in months this year */
559 ? months[tm.tm_mon - 1]
560 : 0) +
561 (tm.tm_mon > 1 && /* Leap day this year */
562 !((tm.tm_year - 72) & 3)) +
563 tm.tm_mday - 1) * 24) + /* Day of month */
564 tm.tm_hour) * 60) +
565 tm.tm_min) * 60) + tm.tm_sec;
566
567 /*
568 * This guess could be wrong because of leap seconds or other
569 * weirdness we don't know about that the system does. For
570 * now, we're just going to accept the guess, but at some point
571 * it might be nice to do a successive approximation here to get
572 * an exact value. Even if the error is small, if the server
573 * is restarted frequently (and thus the lease database is
574 * reread), the error could accumulate into something
575 * significant.
576 */
577 return (guess);
578}