2
3/* Common parser code for dhcpd and dhclient. */
4
5/*
6 * Copyright (c) 1995, 1996, 1997, 1998 The Internet Software Consortium.
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 *
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of The Internet Software Consortium nor the names
19 * of its contributors may be used to endorse or promote products derived
20 * from this software without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
23 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
24 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
25 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
26 * DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
27 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
29 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
30 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
31 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
32 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
33 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * This software has been written for the Internet Software Consortium
37 * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
38 * Enterprises. To learn more about the Internet Software Consortium,
39 * see ``http://www.vix.com/isc''. To learn more about Vixie
40 * Enterprises, see ``http://www.vix.com''.
41 */
42
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46#include "dhcpd.h"
47#include "dhctoken.h"
48
49/* Skip to the semicolon ending the current statement. If we encounter
50 * braces, the matching closing brace terminates the statement. If we
51 * encounter a right brace but haven't encountered a left brace, return
52 * leaving the brace in the token buffer for the caller. If we see a
53 * semicolon and haven't seen a left brace, return. This lets us skip
54 * over:
55 *
56 * statement;
57 * statement foo bar { }
58 * statement foo bar { statement { } }
59 * statement}
60 *
61 * ...et cetera.
62 */
63void
64skip_to_semi(FILE *cfile)
65{
66 int brace_count = 0, token;
67 char *val;
68
69 do {
70 token = peek_token(&val, cfile);
71 if (token == RBRACE) {
72 if (brace_count) {
73 token = next_token(&val, cfile);
74 if (!--brace_count)
75 return;
76 } else
77 return;
78 } else if (token == LBRACE) {
79 brace_count++;
80 } else if (token == SEMI && !brace_count) {
81 token = next_token(&val, cfile);
82 return;
83 } else if (token == '\n') {
84 /*
85 * EOL only happens when parsing
86 * /etc/resolv.conf, and we treat it like a
87 * semicolon because the resolv.conf file is
88 * line-oriented.
89 */
90 token = next_token(&val, cfile);
91 return;
92 }
93 token = next_token(&val, cfile);
94 } while (token != EOF);
95}
96
97int
98parse_semi(FILE *cfile)
99{
100 int token;
101 char *val;
102
103 token = next_token(&val, cfile);
104 if (token != SEMI) {
105 parse_warn("semicolon expected.");
106 skip_to_semi(cfile);
107 return (0);
108 }
109 return (1);
110}
111
112/*
113 * string-parameter :== STRING SEMI
114 */
115char *
116parse_string(FILE *cfile)
117{
118 char *val, *s;
119 int token;
120
121 token = next_token(&val, cfile);
122 if (token != STRING) {
123 parse_warn("filename must be a string");
124 skip_to_semi(cfile);
125 return (NULL);
126 }
127 s = malloc(strlen(val) + 1);
128 if (!s)
129 error("no memory for string %s.", val);
130 strlcpy(s, val, strlen(val) + 1);
131
132 if (!parse_semi(cfile))
133 return (NULL);
134 return (s);
135}
136
137int
138parse_ip_addr(FILE *cfile, struct iaddr *addr)
139{
140 addr->len = 4;
141 if (parse_numeric_aggregate(cfile, addr->iabuf,
142 &addr->len, DOT, 10, 8))
143 return (1);
144 return (0);
145}
146
147/*
148 * hardware-parameter :== HARDWARE ETHERNET csns SEMI
149 * csns :== NUMBER | csns COLON NUMBER
150 */
151void
152parse_hardware_param(FILE *cfile, struct hardware *hardware)
153{
154 unsigned char *t;
155 int token, hlen;
156 char *val;
157
158 token = next_token(&val, cfile);
159 switch (token) {
160 case ETHERNET:
161 hardware->htype = HTYPE_ETHER;
162 break;
163 case TOKEN_RING:
164 hardware->htype = HTYPE_IEEE802;
165 break;
166 case FDDI:
167 hardware->htype = HTYPE_FDDI;
168 break;
169 default:
170 parse_warn("expecting a network hardware type");
171 skip_to_semi(cfile);
172 return;
173 }
174
175 /*
176 * Parse the hardware address information. Technically, it
177 * would make a lot of sense to restrict the length of the data
178 * we'll accept here to the length of a particular hardware
179 * address type. Unfortunately, there are some broken clients
180 * out there that put bogus data in the chaddr buffer, and we
181 * accept that data in the lease file rather than simply failing
182 * on such clients. Yuck.
183 */
184 hlen = 0;
185 t = parse_numeric_aggregate(cfile, NULL, &hlen, COLON, 16, 8);
186 if (!t)
187 return;
188 if (hlen > sizeof(hardware->haddr)) {
189 free(t);
190 parse_warn("hardware address too long");
191 } else {
192 hardware->hlen = hlen;
193 memcpy((unsigned char *)&hardware->haddr[0], t,
194 hardware->hlen);
195 if (hlen < sizeof(hardware->haddr))
196 memset(&hardware->haddr[hlen], 0,
197 sizeof(hardware->haddr) - hlen);
198 free(t);
199 }
200
201 token = next_token(&val, cfile);
202 if (token != SEMI) {
203 parse_warn("expecting semicolon.");
204 skip_to_semi(cfile);
205 }
206}
207
208/*
209 * lease-time :== NUMBER SEMI
210 */
211void
212parse_lease_time(FILE *cfile, time_t *timep)
213{
214 char *val;
215 int token;
216
217 token = next_token(&val, cfile);
218 if (token != NUMBER) {
219 parse_warn("Expecting numeric lease time");
220 skip_to_semi(cfile);
221 return;
222 }
223 convert_num((unsigned char *)timep, val, 10, 32);
224 /* Unswap the number - convert_num returns stuff in NBO. */
225 *timep = ntohl(*timep); /* XXX */
226
227 parse_semi(cfile);
228}
229
230/*
231 * No BNF for numeric aggregates - that's defined by the caller. What
232 * this function does is to parse a sequence of numbers separated by the
233 * token specified in separator. If max is zero, any number of numbers
234 * will be parsed; otherwise, exactly max numbers are expected. Base
235 * and size tell us how to internalize the numbers once they've been
236 * tokenized.
237 */
238unsigned char *
239parse_numeric_aggregate(FILE *cfile, unsigned char *buf, int *max,
240 int separator, int base, int size)
241{
242 unsigned char *bufp = buf, *s = NULL;
243 int token, count = 0;
244 char *val, *t;
245 pair c = NULL;
246
247 if (!bufp && *max) {
248 bufp = malloc(*max * size / 8);
249 if (!bufp)
250 error("can't allocate space for numeric aggregate");
251 } else
252 s = bufp;
253
254 do {
255 if (count) {
256 token = peek_token(&val, cfile);
257 if (token != separator) {
258 if (!*max)
259 break;
260 if (token != RBRACE && token != LBRACE)
261 token = next_token(&val, cfile);
262 parse_warn("too few numbers.");
263 if (token != SEMI)
264 skip_to_semi(cfile);
265 return (NULL);
266 }
267 token = next_token(&val, cfile);
268 }
269 token = next_token(&val, cfile);
270
271 if (token == EOF) {
272 parse_warn("unexpected end of file");
273 break;
274 }
275
276 /* Allow NUMBER_OR_NAME if base is 16. */
277 if (token != NUMBER &&
278 (base != 16 || token != NUMBER_OR_NAME)) {
279 parse_warn("expecting numeric value.");
280 skip_to_semi(cfile);
281 return (NULL);
282 }
283 /*
284 * If we can, convert the number now; otherwise, build a
285 * linked list of all the numbers.
286 */
287 if (s) {
288 convert_num(s, val, base, size);
289 s += size / 8;
290 } else {
291 t = malloc(strlen(val) + 1);
292 if (!t)
293 error("no temp space for number.");
294 strlcpy(t, val, strlen(val) + 1);
295 c = cons(t, c);
296 }
297 } while (++count != *max);
298
299 /* If we had to cons up a list, convert it now. */
300 if (c) {
301 bufp = malloc(count * size / 8);
302 if (!bufp)
303 error("can't allocate space for numeric aggregate.");
304 s = bufp + count - size / 8;
305 *max = count;
306 }
307 while (c) {
308 pair cdr = c->cdr;
309 convert_num(s, (char *)c->car, base, size);
310 s -= size / 8;
311 /* Free up temp space. */
312 free(c->car);
313 free(c);
314 c = cdr;
315 }
316 return (bufp);
317}
318
319void
320convert_num(unsigned char *buf, char *str, int base, int size)
321{
322 int negative = 0, tval, max;
323 u_int32_t val = 0;
324 char *ptr = str;
325
326 if (*ptr == '-') {
327 negative = 1;
328 ptr++;
329 }
330
331 /* If base wasn't specified, figure it out from the data. */
332 if (!base) {
333 if (ptr[0] == '0') {
334 if (ptr[1] == 'x') {
335 base = 16;
336 ptr += 2;
337 } else if (isascii(ptr[1]) && isdigit(ptr[1])) {
338 base = 8;
339 ptr += 1;
340 } else
341 base = 10;
342 } else
343 base = 10;
344 }
345
346 do {
347 tval = *ptr++;
348 /* XXX assumes ASCII... */
349 if (tval >= 'a')
350 tval = tval - 'a' + 10;
351 else if (tval >= 'A')
352 tval = tval - 'A' + 10;
353 else if (tval >= '0')
354 tval -= '0';
355 else {
356 warning("Bogus number: %s.", str);
357 break;
358 }
359 if (tval >= base) {
360 warning("Bogus number: %s: digit %d not in base %d",
361 str, tval, base);
362 break;
363 }
364 val = val * base + tval;
365 } while (*ptr);
366
367 if (negative)
368 max = (1 << (size - 1));
369 else
370 max = (1 << (size - 1)) + ((1 << (size - 1)) - 1);
371 if (val > max) {
372 switch (base) {
373 case 8:
374 warning("value %s%o exceeds max (%d) for precision.",
375 negative ? "-" : "", val, max);
376 break;
377 case 16:
378 warning("value %s%x exceeds max (%d) for precision.",
379 negative ? "-" : "", val, max);
380 break;
381 default:
382 warning("value %s%u exceeds max (%d) for precision.",
383 negative ? "-" : "", val, max);
384 break;
385 }
386 }
387
388 if (negative)
389 switch (size) {
390 case 8:
391 *buf = -(unsigned long)val;
392 break;
393 case 16:
394 putShort(buf, -(unsigned long)val);
395 break;
396 case 32:
397 putLong(buf, -(unsigned long)val);
398 break;
399 default:
400 warning("Unexpected integer size: %d", size);
401 break;
402 }
403 else
404 switch (size) {
405 case 8:
406 *buf = (u_int8_t)val;
407 break;
408 case 16:
409 putUShort(buf, (u_int16_t)val);
410 break;
411 case 32:
412 putULong(buf, val);
413 break;
414 default:
415 warning("Unexpected integer size: %d", size);
416 break;
417 }
418}
419
420/*
421 * date :== NUMBER NUMBER SLASH NUMBER SLASH NUMBER
422 * NUMBER COLON NUMBER COLON NUMBER SEMI
423 *
424 * Dates are always in GMT; first number is day of week; next is
425 * year/month/day; next is hours:minutes:seconds on a 24-hour
426 * clock.
427 */
428time_t
429parse_date(FILE *cfile)
430{
431 static int months[11] = { 31, 59, 90, 120, 151, 181,
432 212, 243, 273, 304, 334 };
433 int guess, token;
434 struct tm tm;
435 char *val;
436
437 /* Day of week... */
438 token = next_token(&val, cfile);
439 if (token != NUMBER) {
440 parse_warn("numeric day of week expected.");
441 if (token != SEMI)
442 skip_to_semi(cfile);
443 return (0);
444 }
445 tm.tm_wday = atoi(val);
446
447 /* Year... */
448 token = next_token(&val, cfile);
449 if (token != NUMBER) {
450 parse_warn("numeric year expected.");
451 if (token != SEMI)
452 skip_to_semi(cfile);
453 return (0);
454 }
455 tm.tm_year = atoi(val);
456 if (tm.tm_year > 1900)
457 tm.tm_year -= 1900;
458
459 /* Slash separating year from month... */
460 token = next_token(&val, cfile);
461 if (token != SLASH) {
462 parse_warn("expected slash separating year from month.");
463 if (token != SEMI)
464 skip_to_semi(cfile);
465 return (0);
466 }
467
468 /* Month... */
469 token = next_token(&val, cfile);
470 if (token != NUMBER) {
471 parse_warn("numeric month expected.");
472 if (token != SEMI)
473 skip_to_semi(cfile);
474 return (0);
475 }
476 tm.tm_mon = atoi(val) - 1;
477
478 /* Slash separating month from day... */
479 token = next_token(&val, cfile);
480 if (token != SLASH) {
481 parse_warn("expected slash separating month from day.");
482 if (token != SEMI)
483 skip_to_semi(cfile);
484 return (0);
485 }
486
487 /* Month... */
488 token = next_token(&val, cfile);
489 if (token != NUMBER) {
490 parse_warn("numeric day of month expected.");
491 if (token != SEMI)
492 skip_to_semi(cfile);
493 return (0);
494 }
495 tm.tm_mday = atoi(val);
496
497 /* Hour... */
498 token = next_token(&val, cfile);
499 if (token != NUMBER) {
500 parse_warn("numeric hour expected.");
501 if (token != SEMI)
502 skip_to_semi(cfile);
503 return (0);
504 }
505 tm.tm_hour = atoi(val);
506
507 /* Colon separating hour from minute... */
508 token = next_token(&val, cfile);
509 if (token != COLON) {
510 parse_warn("expected colon separating hour from minute.");
511 if (token != SEMI)
512 skip_to_semi(cfile);
513 return (0);
514 }
515
516 /* Minute... */
517 token = next_token(&val, cfile);
518 if (token != NUMBER) {
519 parse_warn("numeric minute expected.");
520 if (token != SEMI)
521 skip_to_semi(cfile);
522 return (0);
523 }
524 tm.tm_min = atoi(val);
525
526 /* Colon separating minute from second... */
527 token = next_token(&val, cfile);
528 if (token != COLON) {
529 parse_warn("expected colon separating hour from minute.");
530 if (token != SEMI)
531 skip_to_semi(cfile);
532 return (0);
533 }
534
535 /* Minute... */
536 token = next_token(&val, cfile);
537 if (token != NUMBER) {
538 parse_warn("numeric minute expected.");
539 if (token != SEMI)
540 skip_to_semi(cfile);
541 return (0);
542 }
543 tm.tm_sec = atoi(val);
544 tm.tm_isdst = 0;
545
546 /* XXX: We assume that mktime does not use tm_yday. */
547 tm.tm_yday = 0;
548
549 /* Make sure the date ends in a semicolon... */
550 token = next_token(&val, cfile);
551 if (token != SEMI) {
552 parse_warn("semicolon expected.");
553 skip_to_semi(cfile);
554 return (0);
555 }
556
557 /* Guess the time value... */
558 guess = ((((((365 * (tm.tm_year - 70) + /* Days in years since '70 */
559 (tm.tm_year - 69) / 4 + /* Leap days since '70 */
560 (tm.tm_mon /* Days in months this year */
561 ? months[tm.tm_mon - 1]
562 : 0) +
563 (tm.tm_mon > 1 && /* Leap day this year */
564 !((tm.tm_year - 72) & 3)) +
565 tm.tm_mday - 1) * 24) + /* Day of month */
566 tm.tm_hour) * 60) +
567 tm.tm_min) * 60) + tm.tm_sec;
568
569 /*
570 * This guess could be wrong because of leap seconds or other
571 * weirdness we don't know about that the system does. For
572 * now, we're just going to accept the guess, but at some point
573 * it might be nice to do a successive approximation here to get
574 * an exact value. Even if the error is small, if the server
575 * is restarted frequently (and thus the lease database is
576 * reread), the error could accumulate into something
577 * significant.
578 */
579 return (guess);
580}
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