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