1 /* $OpenBSD: src/sbin/dhclient/parse.c,v 1.20 2011/12/10 17:15:27 krw Exp $ */
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
43 #include "dhcpd.h"
44 #include "dhctoken.h"
45
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 */
61 void
skip_to_semi(FILE * cfile)62 skip_to_semi(FILE *cfile)
63 {
64 int token;
65 int brace_count = 0;
66
67 do {
68 token = peek_token(NULL, cfile);
69 if (token == '}') {
70 if (brace_count) {
71 token = next_token(NULL, cfile);
72 if (!--brace_count)
73 return;
74 } else
75 return;
76 } else if (token == '{') {
77 brace_count++;
78 } else if (token == ';' && !brace_count) {
79 token = next_token(NULL, 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(NULL, cfile);
89 return;
90 }
91 token = next_token(NULL, cfile);
92 } while (token != EOF);
93 }
94
95 int
parse_semi(FILE * cfile)96 parse_semi(FILE *cfile)
97 {
98 int token;
99
100 token = next_token(NULL, cfile);
101 if (token != ';') {
102 parse_warn("semicolon expected.");
103 skip_to_semi(cfile);
104 return (0);
105 }
106 return (1);
107 }
108
109 /*
110 * string-parameter :== STRING SEMI
111 */
112 char *
parse_string(FILE * cfile)113 parse_string(FILE *cfile)
114 {
115 char *val, *s;
116 int token;
117
118 token = next_token(&val, cfile);
119 if (token != TOK_STRING) {
120 parse_warn("filename must be a string");
121 skip_to_semi(cfile);
122 return (NULL);
123 }
124 s = strdup(val);
125 if (!s)
126 error("no memory for string %s.", val);
127
128 if (!parse_semi(cfile)) {
129 free(s);
130 return (NULL);
131 }
132 return (s);
133 }
134
135 int
parse_ip_addr(FILE * cfile,struct iaddr * addr)136 parse_ip_addr(FILE *cfile, struct iaddr *addr)
137 {
138 addr->len = 4;
139 return (parse_numeric_aggregate(cfile, addr->iabuf, addr->len, '.',
140 10));
141 }
142
143 /*
144 * hardware-parameter :== HARDWARE ETHERNET csns SEMI
145 * csns :== NUMBER | csns COLON NUMBER
146 */
147 void
parse_hardware_param(FILE * cfile,struct hardware * hardware)148 parse_hardware_param(FILE *cfile, struct hardware *hardware)
149 {
150 int token;
151
152 token = next_token(NULL, cfile);
153 switch (token) {
154 case TOK_ETHERNET:
155 hardware->htype = HTYPE_ETHER;
156 hardware->hlen = 6;
157 break;
158 case TOK_TOKEN_RING:
159 hardware->htype = HTYPE_IEEE802;
160 hardware->hlen = 6;
161 break;
162 case TOK_FDDI:
163 hardware->htype = HTYPE_FDDI;
164 hardware->hlen = 6;
165 break;
166 default:
167 parse_warn("expecting a network hardware type");
168 skip_to_semi(cfile);
169 return;
170 }
171
172 if (parse_numeric_aggregate(cfile, hardware->haddr, hardware->hlen,
173 ':', 16) == 0)
174 return;
175
176 token = next_token(NULL, cfile);
177 if (token != ';') {
178 parse_warn("expecting semicolon.");
179 skip_to_semi(cfile);
180 }
181 }
182
183 /*
184 * lease-time :== NUMBER SEMI
185 */
186 void
parse_lease_time(FILE * cfile,time_t * timep)187 parse_lease_time(FILE *cfile, time_t *timep)
188 {
189 char *val;
190 int token;
191
192 token = next_token(&val, cfile);
193 if (token != TOK_NUMBER) {
194 parse_warn("Expecting numeric lease time");
195 skip_to_semi(cfile);
196 return;
197 }
198 convert_num((unsigned char *)timep, val, 10, 32);
199 /* Unswap the number - convert_num returns stuff in NBO. */
200 *timep = ntohl(*timep); /* XXX */
201
202 parse_semi(cfile);
203 }
204
205 /*
206 * Parse a sequence of numbers separated by the token specified in separator.
207 * Exactly max numbers are expected.
208 */
209 int
parse_numeric_aggregate(FILE * cfile,unsigned char * buf,int max,int separator,int base)210 parse_numeric_aggregate(FILE *cfile, unsigned char *buf, int max, int separator,
211 int base)
212 {
213 char *val;
214 int token, count;
215
216 if (buf == NULL || max == 0)
217 error("no space for numeric aggregate");
218
219 for (count = 0; count < max; count++, buf++) {
220 if (count && (peek_token(&val, cfile) == separator))
221 token = next_token(&val, cfile);
222
223 token = next_token(&val, cfile);
224
225 if (token == TOK_NUMBER || (base == 16 && token == TOK_NUMBER_OR_NAME))
226 /* XXX Need to check if conversion was successful. */
227 convert_num(buf, val, base, 8);
228 else
229 break;
230 }
231
232 if (count < max) {
233 parse_warn("numeric aggregate too short.");
234 return (0);
235 }
236
237 return (1);
238 }
239
240 void
convert_num(unsigned char * buf,char * str,int base,int size)241 convert_num(unsigned char *buf, char *str, int base, int size)
242 {
243 int negative = 0, tval, max;
244 u_int32_t val = 0;
245 char *ptr = str;
246
247 if (*ptr == '-') {
248 negative = 1;
249 ptr++;
250 }
251
252 /* If base wasn't specified, figure it out from the data. */
253 if (!base) {
254 if (ptr[0] == '0') {
255 if (ptr[1] == 'x') {
256 base = 16;
257 ptr += 2;
258 } else if (isascii(ptr[1]) && isdigit(ptr[1])) {
259 base = 8;
260 ptr += 1;
261 } else
262 base = 10;
263 } else
264 base = 10;
265 }
266
267 do {
268 tval = *ptr++;
269 /* XXX assumes ASCII... */
270 if (tval >= 'a')
271 tval = tval - 'a' + 10;
272 else if (tval >= 'A')
273 tval = tval - 'A' + 10;
274 else if (tval >= '0')
275 tval -= '0';
276 else {
277 warning("Bogus number: %s.", str);
278 break;
279 }
280 if (tval >= base) {
281 warning("Bogus number: %s: digit %d not in base %d",
282 str, tval, base);
283 break;
284 }
285 val = val * base + tval;
286 } while (*ptr);
287
288 if (negative)
289 max = (1 << (size - 1));
290 else
291 max = (1 << (size - 1)) + ((1 << (size - 1)) - 1);
292 if (val > max) {
293 switch (base) {
294 case 8:
295 warning("value %s%o exceeds max (%d) for precision.",
296 negative ? "-" : "", val, max);
297 break;
298 case 16:
299 warning("value %s%x exceeds max (%d) for precision.",
300 negative ? "-" : "", val, max);
301 break;
302 default:
303 warning("value %s%u exceeds max (%d) for precision.",
304 negative ? "-" : "", val, max);
305 break;
306 }
307 }
308
309 if (negative)
310 switch (size) {
311 case 8:
312 *buf = -(unsigned long)val;
313 break;
314 case 16:
315 putShort(buf, -(unsigned long)val);
316 break;
317 case 32:
318 putLong(buf, -(unsigned long)val);
319 break;
320 default:
321 warning("Unexpected integer size: %d", size);
322 break;
323 }
324 else
325 switch (size) {
326 case 8:
327 *buf = (u_int8_t)val;
328 break;
329 case 16:
330 putUShort(buf, (u_int16_t)val);
331 break;
332 case 32:
333 putULong(buf, val);
334 break;
335 default:
336 warning("Unexpected integer size: %d", size);
337 break;
338 }
339 }
340
341 /*
342 * date :== NUMBER NUMBER SLASH NUMBER SLASH NUMBER
343 * NUMBER COLON NUMBER COLON NUMBER SEMI
344 *
345 * Dates are always in GMT; first number is day of week; next is
346 * year/month/day; next is hours:minutes:seconds on a 24-hour
347 * clock.
348 */
349 time_t
parse_date(FILE * cfile)350 parse_date(FILE *cfile)
351 {
352 static int months[11] = { 31, 59, 90, 120, 151, 181,
353 212, 243, 273, 304, 334 };
354 int guess, token;
355 struct tm tm;
356 char *val;
357
358 /* Day of week... */
359 token = next_token(&val, cfile);
360 if (token != TOK_NUMBER) {
361 parse_warn("numeric day of week expected.");
362 if (token != ';')
363 skip_to_semi(cfile);
364 return (0);
365 }
366 tm.tm_wday = atoi(val);
367
368 /* Year... */
369 token = next_token(&val, cfile);
370 if (token != TOK_NUMBER) {
371 parse_warn("numeric year expected.");
372 if (token != ';')
373 skip_to_semi(cfile);
374 return (0);
375 }
376 tm.tm_year = atoi(val);
377 if (tm.tm_year > 1900)
378 tm.tm_year -= 1900;
379
380 /* Slash separating year from month... */
381 token = next_token(&val, cfile);
382 if (token != '/') {
383 parse_warn("expected slash separating year from month.");
384 if (token != ';')
385 skip_to_semi(cfile);
386 return (0);
387 }
388
389 /* Month... */
390 token = next_token(&val, cfile);
391 if (token != TOK_NUMBER) {
392 parse_warn("numeric month expected.");
393 if (token != ';')
394 skip_to_semi(cfile);
395 return (0);
396 }
397 tm.tm_mon = atoi(val) - 1;
398
399 /* Slash separating month from day... */
400 token = next_token(&val, cfile);
401 if (token != '/') {
402 parse_warn("expected slash separating month from day.");
403 if (token != ';')
404 skip_to_semi(cfile);
405 return (0);
406 }
407
408 /* Day... */
409 token = next_token(&val, cfile);
410 if (token != TOK_NUMBER) {
411 parse_warn("numeric day of month expected.");
412 if (token != ';')
413 skip_to_semi(cfile);
414 return (0);
415 }
416 tm.tm_mday = atoi(val);
417
418 /* Hour... */
419 token = next_token(&val, cfile);
420 if (token != TOK_NUMBER) {
421 parse_warn("numeric hour expected.");
422 if (token != ';')
423 skip_to_semi(cfile);
424 return (0);
425 }
426 tm.tm_hour = atoi(val);
427
428 /* Colon separating hour from minute... */
429 token = next_token(&val, cfile);
430 if (token != ':') {
431 parse_warn("expected colon separating hour from minute.");
432 if (token != ';')
433 skip_to_semi(cfile);
434 return (0);
435 }
436
437 /* Minute... */
438 token = next_token(&val, cfile);
439 if (token != TOK_NUMBER) {
440 parse_warn("numeric minute expected.");
441 if (token != ';')
442 skip_to_semi(cfile);
443 return (0);
444 }
445 tm.tm_min = atoi(val);
446
447 /* Colon separating minute from second... */
448 token = next_token(&val, cfile);
449 if (token != ':') {
450 parse_warn("expected colon separating minute from second.");
451 if (token != ';')
452 skip_to_semi(cfile);
453 return (0);
454 }
455
456 /* Second... */
457 token = next_token(&val, cfile);
458 if (token != TOK_NUMBER) {
459 parse_warn("numeric second expected.");
460 if (token != ';')
461 skip_to_semi(cfile);
462 return (0);
463 }
464 tm.tm_sec = atoi(val);
465 tm.tm_isdst = 0;
466
467 /* XXX: We assume that mktime does not use tm_yday. */
468 tm.tm_yday = 0;
469
470 /* Make sure the date ends in a semicolon... */
471 token = next_token(&val, cfile);
472 if (token != ';') {
473 parse_warn("semicolon expected.");
474 skip_to_semi(cfile);
475 return (0);
476 }
477
478 /* Guess the time value... */
479 guess = ((((((365 * (tm.tm_year - 70) + /* Days in years since '70 */
480 (tm.tm_year - 69) / 4 + /* Leap days since '70 */
481 (tm.tm_mon /* Days in months this year */
482 ? months[tm.tm_mon - 1] : 0) +
483 (tm.tm_mon > 1 && /* Leap day this year */
484 !((tm.tm_year - 72) & 3)) +
485 tm.tm_mday - 1) * 24) + /* Day of month */
486 tm.tm_hour) * 60) + tm.tm_min) * 60) + tm.tm_sec;
487
488 /*
489 * This guess could be wrong because of leap seconds or other
490 * weirdness we don't know about that the system does. For
491 * now, we're just going to accept the guess, but at some point
492 * it might be nice to do a successive approximation here to get
493 * an exact value. Even if the error is small, if the server
494 * is restarted frequently (and thus the lease database is
495 * reread), the error could accumulate into something
496 * significant.
497 */
498 return (guess);
499 }
500