xref: /freebsd/contrib/ldns/util.c (revision d2ce15bd43b3a1dcce08eecbff8d5d359946d972)
1 /*
2  * util.c
3  *
4  * some general memory functions
5  *
6  * a Net::DNS like library for C
7  *
8  * (c) NLnet Labs, 2004-2006
9  *
10  * See the file LICENSE for the license
11  */
12 
13 #include <ldns/config.h>
14 
15 #include <ldns/rdata.h>
16 #include <ldns/rr.h>
17 #include <ldns/util.h>
18 #include <strings.h>
19 #include <stdlib.h>
20 #include <stdio.h>
21 #include <sys/time.h>
22 #include <time.h>
23 
24 #ifdef HAVE_SSL
25 #include <openssl/rand.h>
26 #endif
27 
28 #if 0
29 /* put this here tmp. for debugging */
30 static void
31 xprintf_rdf(ldns_rdf *rd)
32 {
33 	/* assume printable string */
34 	fprintf(stderr, "size\t:%u\n", (unsigned int)ldns_rdf_size(rd));
35 	fprintf(stderr, "type\t:%u\n", (unsigned int)ldns_rdf_get_type(rd));
36 	fprintf(stderr, "data\t:[%.*s]\n", (int)ldns_rdf_size(rd),
37 			(char*)ldns_rdf_data(rd));
38 }
39 
40 static void
41 xprintf_rr(ldns_rr *rr)
42 {
43 	/* assume printable string */
44 	uint16_t count, i;
45 
46 	count = ldns_rr_rd_count(rr);
47 
48 	for(i = 0; i < count; i++) {
49 		fprintf(stderr, "print rd %u\n", (unsigned int) i);
50 		xprintf_rdf(rr->_rdata_fields[i]);
51 	}
52 }
53 
54 static void
55 xprintf_hex(uint8_t *data, size_t len)
56 {
57 	size_t i;
58 	for (i = 0; i < len; i++) {
59 		if (i > 0 && i % 20 == 0) {
60 			printf("\t; %u - %u\n", (unsigned int) i - 19, (unsigned int) i);
61 		}
62 		printf("%02x ", (unsigned int) data[i]);
63 	}
64 	printf("\n");
65 }
66 #endif
67 
68 ldns_lookup_table *
69 ldns_lookup_by_name(ldns_lookup_table *table, const char *name)
70 {
71 	while (table->name != NULL) {
72 		if (strcasecmp(name, table->name) == 0)
73 			return table;
74 		table++;
75 	}
76 	return NULL;
77 }
78 
79 ldns_lookup_table *
80 ldns_lookup_by_id(ldns_lookup_table *table, int id)
81 {
82 	while (table->name != NULL) {
83 		if (table->id == id)
84 			return table;
85 		table++;
86 	}
87 	return NULL;
88 }
89 
90 int
91 ldns_get_bit(uint8_t bits[], size_t index)
92 {
93 	/*
94 	 * The bits are counted from left to right, so bit #0 is the
95 	 * left most bit.
96 	 */
97 	return (int) (bits[index / 8] & (1 << (7 - index % 8)));
98 }
99 
100 int
101 ldns_get_bit_r(uint8_t bits[], size_t index)
102 {
103 	/*
104 	 * The bits are counted from right to left, so bit #0 is the
105 	 * right most bit.
106 	 */
107 	return (int) bits[index / 8] & (1 << (index % 8));
108 }
109 
110 void
111 ldns_set_bit(uint8_t *byte, int bit_nr, bool value)
112 {
113 	/*
114 	 * The bits are counted from right to left, so bit #0 is the
115 	 * right most bit.
116 	 */
117 	if (bit_nr >= 0 && bit_nr < 8) {
118 		if (value) {
119 			*byte = *byte | (0x01 << bit_nr);
120 		} else {
121 			*byte = *byte & ~(0x01 << bit_nr);
122 		}
123 	}
124 }
125 
126 int
127 ldns_hexdigit_to_int(char ch)
128 {
129 	switch (ch) {
130 	case '0': return 0;
131 	case '1': return 1;
132 	case '2': return 2;
133 	case '3': return 3;
134 	case '4': return 4;
135 	case '5': return 5;
136 	case '6': return 6;
137 	case '7': return 7;
138 	case '8': return 8;
139 	case '9': return 9;
140 	case 'a': case 'A': return 10;
141 	case 'b': case 'B': return 11;
142 	case 'c': case 'C': return 12;
143 	case 'd': case 'D': return 13;
144 	case 'e': case 'E': return 14;
145 	case 'f': case 'F': return 15;
146 	default:
147 		return -1;
148 	}
149 }
150 
151 char
152 ldns_int_to_hexdigit(int i)
153 {
154 	switch (i) {
155 	case 0: return '0';
156 	case 1: return '1';
157 	case 2: return '2';
158 	case 3: return '3';
159 	case 4: return '4';
160 	case 5: return '5';
161 	case 6: return '6';
162 	case 7: return '7';
163 	case 8: return '8';
164 	case 9: return '9';
165 	case 10: return 'a';
166 	case 11: return 'b';
167 	case 12: return 'c';
168 	case 13: return 'd';
169 	case 14: return 'e';
170 	case 15: return 'f';
171 	default:
172 		abort();
173 	}
174 }
175 
176 int
177 ldns_hexstring_to_data(uint8_t *data, const char *str)
178 {
179 	size_t i;
180 
181 	if (!str || !data) {
182 		return -1;
183 	}
184 
185 	if (strlen(str) % 2 != 0) {
186 		return -2;
187 	}
188 
189 	for (i = 0; i < strlen(str) / 2; i++) {
190 		data[i] =
191 			16 * (uint8_t) ldns_hexdigit_to_int(str[i*2]) +
192 			(uint8_t) ldns_hexdigit_to_int(str[i*2 + 1]);
193 	}
194 
195 	return (int) i;
196 }
197 
198 const char *
199 ldns_version(void)
200 {
201 	return (char*)LDNS_VERSION;
202 }
203 
204 /* Number of days per month (except for February in leap years). */
205 static const int mdays[] = {
206 	31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
207 };
208 
209 #define LDNS_MOD(x,y) (((x) % (y) < 0) ? ((x) % (y) + (y)) : ((x) % (y)))
210 #define LDNS_DIV(x,y) (((x) % (y) < 0) ? ((x) / (y) -  1 ) : ((x) / (y)))
211 
212 static int
213 is_leap_year(int year)
214 {
215 	return LDNS_MOD(year,   4) == 0 && (LDNS_MOD(year, 100) != 0
216 	    || LDNS_MOD(year, 400) == 0);
217 }
218 
219 static int
220 leap_days(int y1, int y2)
221 {
222 	--y1;
223 	--y2;
224 	return (LDNS_DIV(y2,   4) - LDNS_DIV(y1,   4)) -
225 	       (LDNS_DIV(y2, 100) - LDNS_DIV(y1, 100)) +
226 	       (LDNS_DIV(y2, 400) - LDNS_DIV(y1, 400));
227 }
228 
229 /*
230  * Code adapted from Python 2.4.1 sources (Lib/calendar.py).
231  */
232 time_t
233 ldns_mktime_from_utc(const struct tm *tm)
234 {
235 	int year = 1900 + tm->tm_year;
236 	time_t days = 365 * ((time_t) year - 1970) + leap_days(1970, year);
237 	time_t hours;
238 	time_t minutes;
239 	time_t seconds;
240 	int i;
241 
242 	for (i = 0; i < tm->tm_mon; ++i) {
243 		days += mdays[i];
244 	}
245 	if (tm->tm_mon > 1 && is_leap_year(year)) {
246 		++days;
247 	}
248 	days += tm->tm_mday - 1;
249 
250 	hours = days * 24 + tm->tm_hour;
251 	minutes = hours * 60 + tm->tm_min;
252 	seconds = minutes * 60 + tm->tm_sec;
253 
254 	return seconds;
255 }
256 
257 time_t
258 mktime_from_utc(const struct tm *tm)
259 {
260 	return ldns_mktime_from_utc(tm);
261 }
262 
263 #if SIZEOF_TIME_T <= 4
264 
265 static void
266 ldns_year_and_yday_from_days_since_epoch(int64_t days, struct tm *result)
267 {
268 	int year = 1970;
269 	int new_year;
270 
271 	while (days < 0 || days >= (int64_t) (is_leap_year(year) ? 366 : 365)) {
272 		new_year = year + (int) LDNS_DIV(days, 365);
273 		days -= (new_year - year) * 365;
274 		days -= leap_days(year, new_year);
275 		year  = new_year;
276 	}
277 	result->tm_year = year;
278 	result->tm_yday = (int) days;
279 }
280 
281 /* Number of days per month in a leap year. */
282 static const int leap_year_mdays[] = {
283 	31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
284 };
285 
286 static void
287 ldns_mon_and_mday_from_year_and_yday(struct tm *result)
288 {
289 	int idays = result->tm_yday;
290 	const int *mon_lengths = is_leap_year(result->tm_year) ?
291 					leap_year_mdays : mdays;
292 
293 	result->tm_mon = 0;
294 	while  (idays >= mon_lengths[result->tm_mon]) {
295 		idays -= mon_lengths[result->tm_mon++];
296 	}
297 	result->tm_mday = idays + 1;
298 }
299 
300 static void
301 ldns_wday_from_year_and_yday(struct tm *result)
302 {
303 	result->tm_wday = 4 /* 1-1-1970 was a thursday */
304 			+ LDNS_MOD((result->tm_year - 1970), 7) * LDNS_MOD(365, 7)
305 			+ leap_days(1970, result->tm_year)
306 			+ result->tm_yday;
307 	result->tm_wday = LDNS_MOD(result->tm_wday, 7);
308 	if (result->tm_wday < 0) {
309 		result->tm_wday += 7;
310 	}
311 }
312 
313 static struct tm *
314 ldns_gmtime64_r(int64_t clock, struct tm *result)
315 {
316 	result->tm_isdst = 0;
317 	result->tm_sec   = (int) LDNS_MOD(clock, 60);
318 	clock            =       LDNS_DIV(clock, 60);
319 	result->tm_min   = (int) LDNS_MOD(clock, 60);
320 	clock            =       LDNS_DIV(clock, 60);
321 	result->tm_hour  = (int) LDNS_MOD(clock, 24);
322 	clock            =       LDNS_DIV(clock, 24);
323 
324 	ldns_year_and_yday_from_days_since_epoch(clock, result);
325 	ldns_mon_and_mday_from_year_and_yday(result);
326 	ldns_wday_from_year_and_yday(result);
327 	result->tm_year -= 1900;
328 
329 	return result;
330 }
331 
332 #endif /* SIZEOF_TIME_T <= 4 */
333 
334 static int64_t
335 ldns_serial_arithmitics_time(int32_t time, time_t now)
336 {
337 	int32_t offset = time - (int32_t) now;
338 	return (int64_t) now + offset;
339 }
340 
341 
342 struct tm *
343 ldns_serial_arithmitics_gmtime_r(int32_t time, time_t now, struct tm *result)
344 {
345 #if SIZEOF_TIME_T <= 4
346 	int64_t secs_since_epoch = ldns_serial_arithmitics_time(time, now);
347 	return  ldns_gmtime64_r(secs_since_epoch, result);
348 #else
349 	time_t  secs_since_epoch = ldns_serial_arithmitics_time(time, now);
350 	return  gmtime_r(&secs_since_epoch, result);
351 #endif
352 }
353 
354 /**
355  * Init the random source
356  * applications should call this if they need entropy data within ldns
357  * If openSSL is available, it is automatically seeded from /dev/urandom
358  * or /dev/random
359  *
360  * If you need more entropy, or have no openssl available, this function
361  * MUST be called at the start of the program
362  *
363  * If openssl *is* available, this function just adds more entropy
364  **/
365 int
366 ldns_init_random(FILE *fd, unsigned int size)
367 {
368 	/* if fp is given, seed srandom with data from file
369 	   otherwise use /dev/urandom */
370 	FILE *rand_f;
371 	uint8_t *seed;
372 	size_t read = 0;
373 	unsigned int seed_i;
374 	struct timeval tv;
375 
376 	/* we'll need at least sizeof(unsigned int) bytes for the
377 	   standard prng seed */
378 	if (size < (unsigned int) sizeof(seed_i)){
379 		size = (unsigned int) sizeof(seed_i);
380 	}
381 
382 	seed = LDNS_XMALLOC(uint8_t, size);
383         if(!seed) {
384 		return 1;
385         }
386 
387 	if (!fd) {
388 		if ((rand_f = fopen("/dev/urandom", "r")) == NULL) {
389 			/* no readable /dev/urandom, try /dev/random */
390 			if ((rand_f = fopen("/dev/random", "r")) == NULL) {
391 				/* no readable /dev/random either, and no entropy
392 				   source given. we'll have to improvise */
393 				for (read = 0; read < size; read++) {
394 					gettimeofday(&tv, NULL);
395 					seed[read] = (uint8_t) (tv.tv_usec % 256);
396 				}
397 			} else {
398 				read = fread(seed, 1, size, rand_f);
399 			}
400 		} else {
401 			read = fread(seed, 1, size, rand_f);
402 		}
403 	} else {
404 		rand_f = fd;
405 		read = fread(seed, 1, size, rand_f);
406 	}
407 
408 	if (read < size) {
409 		LDNS_FREE(seed);
410 		if (!fd) fclose(rand_f);
411 		return 1;
412 	} else {
413 #ifdef HAVE_SSL
414 		/* Seed the OpenSSL prng (most systems have it seeded
415 		   automatically, in that case this call just adds entropy */
416 		RAND_seed(seed, (int) size);
417 #else
418 		/* Seed the standard prng, only uses the first
419 		 * unsigned sizeof(unsiged int) bytes found in the entropy pool
420 		 */
421 		memcpy(&seed_i, seed, sizeof(seed_i));
422 		srandom(seed_i);
423 #endif
424 		LDNS_FREE(seed);
425 	}
426 
427 	if (!fd) {
428                 if (rand_f) fclose(rand_f);
429 	}
430 
431 	return 0;
432 }
433 
434 /**
435  * Get random number.
436  *
437  */
438 uint16_t
439 ldns_get_random(void)
440 {
441         uint16_t rid = 0;
442 #ifdef HAVE_SSL
443         if (RAND_bytes((unsigned char*)&rid, 2) != 1) {
444                 rid = (uint16_t) random();
445         }
446 #else
447         rid = (uint16_t) random();
448 #endif
449 	return rid;
450 }
451 
452 /*
453  * BubbleBabble code taken from OpenSSH
454  * Copyright (c) 2001 Carsten Raskgaard.  All rights reserved.
455  */
456 char *
457 ldns_bubblebabble(uint8_t *data, size_t len)
458 {
459 	char vowels[] = { 'a', 'e', 'i', 'o', 'u', 'y' };
460 	char consonants[] = { 'b', 'c', 'd', 'f', 'g', 'h', 'k', 'l', 'm',
461 	    'n', 'p', 'r', 's', 't', 'v', 'z', 'x' };
462 	size_t i, j = 0, rounds, seed = 1;
463 	char *retval;
464 
465 	rounds = (len / 2) + 1;
466 	retval = LDNS_XMALLOC(char, rounds * 6);
467 	if(!retval) return NULL;
468 	retval[j++] = 'x';
469 	for (i = 0; i < rounds; i++) {
470 		size_t idx0, idx1, idx2, idx3, idx4;
471 		if ((i + 1 < rounds) || (len % 2 != 0)) {
472 			idx0 = (((((size_t)(data[2 * i])) >> 6) & 3) +
473 			    seed) % 6;
474 			idx1 = (((size_t)(data[2 * i])) >> 2) & 15;
475 			idx2 = ((((size_t)(data[2 * i])) & 3) +
476 			    (seed / 6)) % 6;
477 			retval[j++] = vowels[idx0];
478 			retval[j++] = consonants[idx1];
479 			retval[j++] = vowels[idx2];
480 			if ((i + 1) < rounds) {
481 				idx3 = (((size_t)(data[(2 * i) + 1])) >> 4) & 15;
482 				idx4 = (((size_t)(data[(2 * i) + 1]))) & 15;
483 				retval[j++] = consonants[idx3];
484 				retval[j++] = '-';
485 				retval[j++] = consonants[idx4];
486 				seed = ((seed * 5) +
487 				    ((((size_t)(data[2 * i])) * 7) +
488 				    ((size_t)(data[(2 * i) + 1])))) % 36;
489 			}
490 		} else {
491 			idx0 = seed % 6;
492 			idx1 = 16;
493 			idx2 = seed / 6;
494 			retval[j++] = vowels[idx0];
495 			retval[j++] = consonants[idx1];
496 			retval[j++] = vowels[idx2];
497 		}
498 	}
499 	retval[j++] = 'x';
500 	retval[j++] = '\0';
501 	return retval;
502 }
503