xref: /dragonfly/contrib/ldns/util.c (revision ec1c3f3a)
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 #include <ctype.h>
24 
25 #ifdef HAVE_SSL
26 #include <openssl/rand.h>
27 #endif
28 
29 ldns_lookup_table *
30 ldns_lookup_by_name(ldns_lookup_table *table, const char *name)
31 {
32 	while (table->name != NULL) {
33 		if (strcasecmp(name, table->name) == 0)
34 			return table;
35 		table++;
36 	}
37 	return NULL;
38 }
39 
40 ldns_lookup_table *
41 ldns_lookup_by_id(ldns_lookup_table *table, int id)
42 {
43 	while (table->name != NULL) {
44 		if (table->id == id)
45 			return table;
46 		table++;
47 	}
48 	return NULL;
49 }
50 
51 int
52 ldns_get_bit(uint8_t bits[], size_t index)
53 {
54 	/*
55 	 * The bits are counted from left to right, so bit #0 is the
56 	 * left most bit.
57 	 */
58 	return (int) (bits[index / 8] & (1 << (7 - index % 8)));
59 }
60 
61 int
62 ldns_get_bit_r(uint8_t bits[], size_t index)
63 {
64 	/*
65 	 * The bits are counted from right to left, so bit #0 is the
66 	 * right most bit.
67 	 */
68 	return (int) bits[index / 8] & (1 << (index % 8));
69 }
70 
71 void
72 ldns_set_bit(uint8_t *byte, int bit_nr, bool value)
73 {
74 	/*
75 	 * The bits are counted from right to left, so bit #0 is the
76 	 * right most bit.
77 	 */
78 	if (bit_nr >= 0 && bit_nr < 8) {
79 		if (value) {
80 			*byte = *byte | (0x01 << bit_nr);
81 		} else {
82 			*byte = *byte & ~(0x01 << bit_nr);
83 		}
84 	}
85 }
86 
87 int
88 ldns_hexdigit_to_int(char ch)
89 {
90 	switch (ch) {
91 	case '0': return 0;
92 	case '1': return 1;
93 	case '2': return 2;
94 	case '3': return 3;
95 	case '4': return 4;
96 	case '5': return 5;
97 	case '6': return 6;
98 	case '7': return 7;
99 	case '8': return 8;
100 	case '9': return 9;
101 	case 'a': case 'A': return 10;
102 	case 'b': case 'B': return 11;
103 	case 'c': case 'C': return 12;
104 	case 'd': case 'D': return 13;
105 	case 'e': case 'E': return 14;
106 	case 'f': case 'F': return 15;
107 	default:
108 		return -1;
109 	}
110 }
111 
112 char
113 ldns_int_to_hexdigit(int i)
114 {
115 	switch (i) {
116 	case 0: return '0';
117 	case 1: return '1';
118 	case 2: return '2';
119 	case 3: return '3';
120 	case 4: return '4';
121 	case 5: return '5';
122 	case 6: return '6';
123 	case 7: return '7';
124 	case 8: return '8';
125 	case 9: return '9';
126 	case 10: return 'a';
127 	case 11: return 'b';
128 	case 12: return 'c';
129 	case 13: return 'd';
130 	case 14: return 'e';
131 	case 15: return 'f';
132 	default:
133 		abort();
134 	}
135 }
136 
137 int
138 ldns_hexstring_to_data(uint8_t *data, const char *str)
139 {
140 	size_t i;
141 
142 	if (!str || !data) {
143 		return -1;
144 	}
145 
146 	if (strlen(str) % 2 != 0) {
147 		return -2;
148 	}
149 
150 	for (i = 0; i < strlen(str) / 2; i++) {
151 		data[i] =
152 			16 * (uint8_t) ldns_hexdigit_to_int(str[i*2]) +
153 			(uint8_t) ldns_hexdigit_to_int(str[i*2 + 1]);
154 	}
155 
156 	return (int) i;
157 }
158 
159 const char *
160 ldns_version(void)
161 {
162 	return (char*)LDNS_VERSION;
163 }
164 
165 /* Number of days per month (except for February in leap years). */
166 static const int mdays[] = {
167 	31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
168 };
169 
170 #define LDNS_MOD(x,y) (((x) % (y) < 0) ? ((x) % (y) + (y)) : ((x) % (y)))
171 #define LDNS_DIV(x,y) (((x) % (y) < 0) ? ((x) / (y) -  1 ) : ((x) / (y)))
172 
173 static int
174 is_leap_year(int year)
175 {
176 	return LDNS_MOD(year,   4) == 0 && (LDNS_MOD(year, 100) != 0
177 	    || LDNS_MOD(year, 400) == 0);
178 }
179 
180 static int
181 leap_days(int y1, int y2)
182 {
183 	--y1;
184 	--y2;
185 	return (LDNS_DIV(y2,   4) - LDNS_DIV(y1,   4)) -
186 	       (LDNS_DIV(y2, 100) - LDNS_DIV(y1, 100)) +
187 	       (LDNS_DIV(y2, 400) - LDNS_DIV(y1, 400));
188 }
189 
190 /*
191  * Code adapted from Python 2.4.1 sources (Lib/calendar.py).
192  */
193 time_t
194 ldns_mktime_from_utc(const struct tm *tm)
195 {
196 	int year = 1900 + tm->tm_year;
197 	time_t days = 365 * ((time_t) year - 1970) + leap_days(1970, year);
198 	time_t hours;
199 	time_t minutes;
200 	time_t seconds;
201 	int i;
202 
203 	for (i = 0; i < tm->tm_mon; ++i) {
204 		days += mdays[i];
205 	}
206 	if (tm->tm_mon > 1 && is_leap_year(year)) {
207 		++days;
208 	}
209 	days += tm->tm_mday - 1;
210 
211 	hours = days * 24 + tm->tm_hour;
212 	minutes = hours * 60 + tm->tm_min;
213 	seconds = minutes * 60 + tm->tm_sec;
214 
215 	return seconds;
216 }
217 
218 time_t
219 mktime_from_utc(const struct tm *tm)
220 {
221 	return ldns_mktime_from_utc(tm);
222 }
223 
224 #if SIZEOF_TIME_T <= 4
225 
226 static void
227 ldns_year_and_yday_from_days_since_epoch(int64_t days, struct tm *result)
228 {
229 	int year = 1970;
230 	int new_year;
231 
232 	while (days < 0 || days >= (int64_t) (is_leap_year(year) ? 366 : 365)) {
233 		new_year = year + (int) LDNS_DIV(days, 365);
234 		days -= (new_year - year) * 365;
235 		days -= leap_days(year, new_year);
236 		year  = new_year;
237 	}
238 	result->tm_year = year;
239 	result->tm_yday = (int) days;
240 }
241 
242 /* Number of days per month in a leap year. */
243 static const int leap_year_mdays[] = {
244 	31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
245 };
246 
247 static void
248 ldns_mon_and_mday_from_year_and_yday(struct tm *result)
249 {
250 	int idays = result->tm_yday;
251 	const int *mon_lengths = is_leap_year(result->tm_year) ?
252 					leap_year_mdays : mdays;
253 
254 	result->tm_mon = 0;
255 	while  (idays >= mon_lengths[result->tm_mon]) {
256 		idays -= mon_lengths[result->tm_mon++];
257 	}
258 	result->tm_mday = idays + 1;
259 }
260 
261 static void
262 ldns_wday_from_year_and_yday(struct tm *result)
263 {
264 	result->tm_wday = 4 /* 1-1-1970 was a thursday */
265 			+ LDNS_MOD((result->tm_year - 1970), 7) * LDNS_MOD(365, 7)
266 			+ leap_days(1970, result->tm_year)
267 			+ result->tm_yday;
268 	result->tm_wday = LDNS_MOD(result->tm_wday, 7);
269 	if (result->tm_wday < 0) {
270 		result->tm_wday += 7;
271 	}
272 }
273 
274 static struct tm *
275 ldns_gmtime64_r(int64_t clock, struct tm *result)
276 {
277 	result->tm_isdst = 0;
278 	result->tm_sec   = (int) LDNS_MOD(clock, 60);
279 	clock            =       LDNS_DIV(clock, 60);
280 	result->tm_min   = (int) LDNS_MOD(clock, 60);
281 	clock            =       LDNS_DIV(clock, 60);
282 	result->tm_hour  = (int) LDNS_MOD(clock, 24);
283 	clock            =       LDNS_DIV(clock, 24);
284 
285 	ldns_year_and_yday_from_days_since_epoch(clock, result);
286 	ldns_mon_and_mday_from_year_and_yday(result);
287 	ldns_wday_from_year_and_yday(result);
288 	result->tm_year -= 1900;
289 
290 	return result;
291 }
292 
293 #endif /* SIZEOF_TIME_T <= 4 */
294 
295 static int64_t
296 ldns_serial_arithmetics_time(int32_t time, time_t now)
297 {
298 	/* Casting due to https://github.com/NLnetLabs/ldns/issues/71 */
299 	int32_t offset = (int32_t) ((uint32_t) time - (uint32_t) now);
300 	return (int64_t) now + offset;
301 }
302 
303 struct tm *
304 ldns_serial_arithmetics_gmtime_r(int32_t time, time_t now, struct tm *result)
305 {
306 #if SIZEOF_TIME_T <= 4
307 	int64_t secs_since_epoch = ldns_serial_arithmetics_time(time, now);
308 	return  ldns_gmtime64_r(secs_since_epoch, result);
309 #else
310 	time_t  secs_since_epoch = ldns_serial_arithmetics_time(time, now);
311 	return  gmtime_r(&secs_since_epoch, result);
312 #endif
313 }
314 
315 #ifdef ldns_serial_arithmitics_gmtime_r
316 #undef ldns_serial_arithmitics_gmtime_r
317 #endif
318 /* alias function because of previously used wrong spelling */
319 struct tm *
320 ldns_serial_arithmitics_gmtime_r(int32_t time, time_t now, struct tm *result)
321 {
322 	return ldns_serial_arithmetics_gmtime_r(time, now, result);
323 }
324 
325 /**
326  * Init the random source
327  * applications should call this if they need entropy data within ldns
328  * If openSSL is available, it is automatically seeded from /dev/urandom
329  * or /dev/random
330  *
331  * If you need more entropy, or have no openssl available, this function
332  * MUST be called at the start of the program
333  *
334  * If openssl *is* available, this function just adds more entropy
335  **/
336 int
337 ldns_init_random(FILE *fd, unsigned int size)
338 {
339 	/* if fp is given, seed srandom with data from file
340 	   otherwise use /dev/urandom */
341 	FILE *rand_f;
342 	uint8_t *seed;
343 	size_t read = 0;
344 	unsigned int seed_i;
345 	struct timeval tv;
346 
347 	/* we'll need at least sizeof(unsigned int) bytes for the
348 	   standard prng seed */
349 	if (size < (unsigned int) sizeof(seed_i)){
350 		size = (unsigned int) sizeof(seed_i);
351 	}
352 
353 	seed = LDNS_XMALLOC(uint8_t, size);
354         if(!seed) {
355 		return 1;
356         }
357 
358 	if (!fd) {
359 		if ((rand_f = fopen("/dev/urandom", "r")) == NULL) {
360 			/* no readable /dev/urandom, try /dev/random */
361 			if ((rand_f = fopen("/dev/random", "r")) == NULL) {
362 				/* no readable /dev/random either, and no entropy
363 				   source given. we'll have to improvise */
364 				for (read = 0; read < size; read++) {
365 					gettimeofday(&tv, NULL);
366 					seed[read] = (uint8_t) (tv.tv_usec % 256);
367 				}
368 			} else {
369 				read = fread(seed, 1, size, rand_f);
370 			}
371 		} else {
372 			read = fread(seed, 1, size, rand_f);
373 		}
374 	} else {
375 		rand_f = fd;
376 		read = fread(seed, 1, size, rand_f);
377 	}
378 
379 	if (read < size) {
380 		LDNS_FREE(seed);
381 		if (!fd) fclose(rand_f);
382 		return 1;
383 	} else {
384 #ifdef HAVE_SSL
385 		/* Seed the OpenSSL prng (most systems have it seeded
386 		   automatically, in that case this call just adds entropy */
387 		RAND_seed(seed, (int) size);
388 #else
389 		/* Seed the standard prng, only uses the first
390 		 * unsigned sizeof(unsigned int) bytes found in the entropy pool
391 		 */
392 		memcpy(&seed_i, seed, sizeof(seed_i));
393 		srandom(seed_i);
394 #endif
395 		LDNS_FREE(seed);
396 	}
397 
398 	if (!fd) {
399                 if (rand_f) fclose(rand_f);
400 	}
401 
402 	return 0;
403 }
404 
405 /**
406  * Get random number.
407  *
408  */
409 uint16_t
410 ldns_get_random(void)
411 {
412         uint16_t rid = 0;
413 #ifdef HAVE_SSL
414         if (RAND_bytes((unsigned char*)&rid, 2) != 1) {
415                 rid = (uint16_t) random();
416         }
417 #else
418         rid = (uint16_t) random();
419 #endif
420 	return rid;
421 }
422 
423 /*
424  * BubbleBabble code taken from OpenSSH
425  * Copyright (c) 2001 Carsten Raskgaard.  All rights reserved.
426  */
427 char *
428 ldns_bubblebabble(uint8_t *data, size_t len)
429 {
430 	char vowels[] = { 'a', 'e', 'i', 'o', 'u', 'y' };
431 	char consonants[] = { 'b', 'c', 'd', 'f', 'g', 'h', 'k', 'l', 'm',
432 	    'n', 'p', 'r', 's', 't', 'v', 'z', 'x' };
433 	size_t i, j = 0, rounds, seed = 1;
434 	char *retval;
435 
436 	rounds = (len / 2) + 1;
437 	retval = LDNS_XMALLOC(char, rounds * 6);
438 	if(!retval) return NULL;
439 	retval[j++] = 'x';
440 	for (i = 0; i < rounds; i++) {
441 		size_t idx0, idx1, idx2, idx3, idx4;
442 		if ((i + 1 < rounds) || (len % 2 != 0)) {
443 			idx0 = (((((size_t)(data[2 * i])) >> 6) & 3) +
444 			    seed) % 6;
445 			idx1 = (((size_t)(data[2 * i])) >> 2) & 15;
446 			idx2 = ((((size_t)(data[2 * i])) & 3) +
447 			    (seed / 6)) % 6;
448 			retval[j++] = vowels[idx0];
449 			retval[j++] = consonants[idx1];
450 			retval[j++] = vowels[idx2];
451 			if ((i + 1) < rounds) {
452 				idx3 = (((size_t)(data[(2 * i) + 1])) >> 4) & 15;
453 				idx4 = (((size_t)(data[(2 * i) + 1]))) & 15;
454 				retval[j++] = consonants[idx3];
455 				retval[j++] = '-';
456 				retval[j++] = consonants[idx4];
457 				seed = ((seed * 5) +
458 				    ((((size_t)(data[2 * i])) * 7) +
459 				    ((size_t)(data[(2 * i) + 1])))) % 36;
460 			}
461 		} else {
462 			idx0 = seed % 6;
463 			idx1 = 16;
464 			idx2 = seed / 6;
465 			retval[j++] = vowels[idx0];
466 			retval[j++] = consonants[idx1];
467 			retval[j++] = vowels[idx2];
468 		}
469 	}
470 	retval[j++] = 'x';
471 	retval[j++] = '\0';
472 	return retval;
473 }
474 
475 /*
476  * For backwards compatibility, because we have always exported this symbol.
477  */
478 #ifdef HAVE_B64_NTOP
479 int ldns_b64_ntop(const uint8_t* src, size_t srclength,
480 		char *target, size_t targsize);
481 {
482 	return b64_ntop(src, srclength, target, targsize);
483 }
484 #endif
485 
486 /*
487  * For backwards compatibility, because we have always exported this symbol.
488  */
489 #ifdef HAVE_B64_PTON
490 int ldns_b64_pton(const char* src, uint8_t *target, size_t targsize)
491 {
492 	return b64_pton(src, target, targsize);
493 }
494 #endif
495 
496 
497 static int
498 ldns_b32_ntop_base(const uint8_t* src, size_t src_sz,
499 		char* dst, size_t dst_sz,
500 		bool extended_hex, bool add_padding)
501 {
502 	size_t ret_sz;
503 	const char* b32 = extended_hex ? "0123456789abcdefghijklmnopqrstuv"
504 	                               : "abcdefghijklmnopqrstuvwxyz234567";
505 
506 	size_t c = 0; /* c is used to carry partial base32 character over
507 	               * byte boundaries for sizes with a remainder.
508 		       * (i.e. src_sz % 5 != 0)
509 		       */
510 
511 	ret_sz = add_padding ? ldns_b32_ntop_calculate_size(src_sz)
512 	                     : ldns_b32_ntop_calculate_size_no_padding(src_sz);
513 
514 	/* Do we have enough space? */
515 	if (dst_sz < ret_sz + 1)
516 		return -1;
517 
518 	/* We know the size; terminate the string */
519 	dst[ret_sz] = '\0';
520 
521 	/* First process all chunks of five */
522 	while (src_sz >= 5) {
523 		/* 00000... ........ ........ ........ ........ */
524 		dst[0] = b32[(src[0]       ) >> 3];
525 
526 		/* .....111 11...... ........ ........ ........ */
527 		dst[1] = b32[(src[0] & 0x07) << 2 | src[1] >> 6];
528 
529 		/* ........ ..22222. ........ ........ ........ */
530 		dst[2] = b32[(src[1] & 0x3e) >> 1];
531 
532 		/* ........ .......3 3333.... ........ ........ */
533 		dst[3] = b32[(src[1] & 0x01) << 4 | src[2] >> 4];
534 
535 		/* ........ ........ ....4444 4....... ........ */
536 		dst[4] = b32[(src[2] & 0x0f) << 1 | src[3] >> 7];
537 
538 		/* ........ ........ ........ .55555.. ........ */
539 		dst[5] = b32[(src[3] & 0x7c) >> 2];
540 
541 		/* ........ ........ ........ ......66 666..... */
542 		dst[6] = b32[(src[3] & 0x03) << 3 | src[4] >> 5];
543 
544 		/* ........ ........ ........ ........ ...77777 */
545 		dst[7] = b32[(src[4] & 0x1f)     ];
546 
547 		src_sz -= 5;
548 		src    += 5;
549 		dst    += 8;
550 	}
551 	/* Process what remains */
552 	switch (src_sz) {
553 	case 4: /* ........ ........ ........ ......66 666..... */
554 		dst[6] = b32[(src[3] & 0x03) << 3];
555 
556 		/* ........ ........ ........ .55555.. ........ */
557 		dst[5] = b32[(src[3] & 0x7c) >> 2];
558 
559 		/* ........ ........ ....4444 4....... ........ */
560 		         c =  src[3]         >> 7 ;
561 		/* fallthrough */
562 	case 3: dst[4] = b32[(src[2] & 0x0f) << 1 | c];
563 
564 		/* ........ .......3 3333.... ........ ........ */
565 			 c =  src[2]         >> 4 ;
566 		/* fallthrough */
567 	case 2:	dst[3] = b32[(src[1] & 0x01) << 4 | c];
568 
569 		/* ........ ..22222. ........ ........ ........ */
570 		dst[2] = b32[(src[1] & 0x3e) >> 1];
571 
572 		/* .....111 11...... ........ ........ ........ */
573 	                 c =  src[1]         >> 6 ;
574 		/* fallthrough */
575 	case 1:	dst[1] = b32[(src[0] & 0x07) << 2 | c];
576 
577 		/* 00000... ........ ........ ........ ........ */
578 		dst[0] = b32[ src[0]         >> 3];
579 	}
580 	/* Add padding */
581 	if (add_padding) {
582 		switch (src_sz) {
583 			case 1: dst[2] = '=';
584 				dst[3] = '=';
585 				/* fallthrough */
586 			case 2: dst[4] = '=';
587 				/* fallthrough */
588 			case 3: dst[5] = '=';
589 				dst[6] = '=';
590 				/* fallthrough */
591 			case 4: dst[7] = '=';
592 		}
593 	}
594 	return (int)ret_sz;
595 }
596 
597 int
598 ldns_b32_ntop(const uint8_t* src, size_t src_sz, char* dst, size_t dst_sz)
599 {
600 	return ldns_b32_ntop_base(src, src_sz, dst, dst_sz, false, true);
601 }
602 
603 int
604 ldns_b32_ntop_extended_hex(const uint8_t* src, size_t src_sz,
605 		char* dst, size_t dst_sz)
606 {
607 	return ldns_b32_ntop_base(src, src_sz, dst, dst_sz, true, true);
608 }
609 
610 #ifndef HAVE_B32_NTOP
611 
612 int
613 b32_ntop(const uint8_t* src, size_t src_sz, char* dst, size_t dst_sz)
614 {
615 	return ldns_b32_ntop_base(src, src_sz, dst, dst_sz, false, true);
616 }
617 
618 int
619 b32_ntop_extended_hex(const uint8_t* src, size_t src_sz,
620 		char* dst, size_t dst_sz)
621 {
622 	return ldns_b32_ntop_base(src, src_sz, dst, dst_sz, true, true);
623 }
624 
625 #endif /* ! HAVE_B32_NTOP */
626 
627 static int
628 ldns_b32_pton_base(const char* src, size_t src_sz,
629 		uint8_t* dst, size_t dst_sz,
630 		bool extended_hex, bool check_padding)
631 {
632 	size_t i = 0;
633 	char ch = '\0';
634 	uint8_t buf[8];
635 	uint8_t* start = dst;
636 
637 	while (src_sz) {
638 		/* Collect 8 characters in buf (if possible) */
639 		for (i = 0; i < 8; i++) {
640 
641 			do {
642 				ch = *src++;
643 				--src_sz;
644 
645 			} while (isspace((unsigned char)ch) && src_sz > 0);
646 
647 			if (ch == '=' || ch == '\0')
648 				break;
649 
650 			else if (extended_hex)
651 
652 				if (ch >= '0' && ch <= '9')
653 					buf[i] = (uint8_t)ch - '0';
654 				else if (ch >= 'a' && ch <= 'v')
655 					buf[i] = (uint8_t)ch - 'a' + 10;
656 				else if (ch >= 'A' && ch <= 'V')
657 					buf[i] = (uint8_t)ch - 'A' + 10;
658 				else
659 					return -1;
660 
661 			else if (ch >= 'a' && ch <= 'z')
662 				buf[i] = (uint8_t)ch - 'a';
663 			else if (ch >= 'A' && ch <= 'Z')
664 				buf[i] = (uint8_t)ch - 'A';
665 			else if (ch >= '2' && ch <= '7')
666 				buf[i] = (uint8_t)ch - '2' + 26;
667 			else
668 				return -1;
669 		}
670 		/* Less that 8 characters. We're done. */
671 		if (i < 8)
672 			break;
673 
674 		/* Enough space available at the destination? */
675 		if (dst_sz < 5)
676 			return -1;
677 
678 		/* 00000... ........ ........ ........ ........ */
679 		/* .....111 11...... ........ ........ ........ */
680 		dst[0] = buf[0] << 3 | buf[1] >> 2;
681 
682 		/* .....111 11...... ........ ........ ........ */
683 		/* ........ ..22222. ........ ........ ........ */
684 		/* ........ .......3 3333.... ........ ........ */
685 		dst[1] = buf[1] << 6 | buf[2] << 1 | buf[3] >> 4;
686 
687 		/* ........ .......3 3333.... ........ ........ */
688 		/* ........ ........ ....4444 4....... ........ */
689 		dst[2] = buf[3] << 4 | buf[4] >> 1;
690 
691 		/* ........ ........ ....4444 4....... ........ */
692 		/* ........ ........ ........ .55555.. ........ */
693 		/* ........ ........ ........ ......66 666..... */
694 		dst[3] = buf[4] << 7 | buf[5] << 2 | buf[6] >> 3;
695 
696 		/* ........ ........ ........ ......66 666..... */
697 		/* ........ ........ ........ ........ ...77777 */
698 		dst[4] = buf[6] << 5 | buf[7];
699 
700 		dst += 5;
701 		dst_sz -= 5;
702 	}
703 	/* Not ending on a eight byte boundary? */
704 	if (i > 0 && i < 8) {
705 
706 		/* Enough space available at the destination? */
707 		if (dst_sz < (i + 1) / 2)
708 			return -1;
709 
710 		switch (i) {
711 		case 7: /* ........ ........ ........ ......66 666..... */
712 			/* ........ ........ ........ .55555.. ........ */
713 			/* ........ ........ ....4444 4....... ........ */
714 			dst[3] = buf[4] << 7 | buf[5] << 2 | buf[6] >> 3;
715 			/* fallthrough */
716 
717 		case 5: /* ........ ........ ....4444 4....... ........ */
718 			/* ........ .......3 3333.... ........ ........ */
719 			dst[2] = buf[3] << 4 | buf[4] >> 1;
720 			/* fallthrough */
721 
722 		case 4: /* ........ .......3 3333.... ........ ........ */
723 			/* ........ ..22222. ........ ........ ........ */
724 			/* .....111 11...... ........ ........ ........ */
725 			dst[1] = buf[1] << 6 | buf[2] << 1 | buf[3] >> 4;
726 			/* fallthrough */
727 
728 		case 2: /* .....111 11...... ........ ........ ........ */
729 			/* 00000... ........ ........ ........ ........ */
730 			dst[0] = buf[0] << 3 | buf[1] >> 2;
731 
732 			break;
733 
734 		default:
735 			return -1;
736 		}
737 		dst += (i + 1) / 2;
738 
739 		if (check_padding) {
740 			/* Check remaining padding characters */
741 			if (ch != '=')
742 				return -1;
743 
744 			/* One down, 8 - i - 1 more to come... */
745 			for (i = 8 - i - 1; i > 0; i--) {
746 
747 				do {
748 					if (src_sz == 0)
749 						return -1;
750 					ch = *src++;
751 					src_sz--;
752 
753 				} while (isspace((unsigned char)ch));
754 
755 				if (ch != '=')
756 					return -1;
757 			}
758 		}
759 	}
760 	return dst - start;
761 }
762 
763 int
764 ldns_b32_pton(const char* src, size_t src_sz, uint8_t* dst, size_t dst_sz)
765 {
766 	return ldns_b32_pton_base(src, src_sz, dst, dst_sz, false, true);
767 }
768 
769 int
770 ldns_b32_pton_extended_hex(const char* src, size_t src_sz,
771 		uint8_t* dst, size_t dst_sz)
772 {
773 	return ldns_b32_pton_base(src, src_sz, dst, dst_sz, true, true);
774 }
775 
776 #ifndef HAVE_B32_PTON
777 
778 int
779 b32_pton(const char* src, size_t src_sz, uint8_t* dst, size_t dst_sz)
780 {
781 	return ldns_b32_pton_base(src, src_sz, dst, dst_sz, false, true);
782 }
783 
784 int
785 b32_pton_extended_hex(const char* src, size_t src_sz,
786 		uint8_t* dst, size_t dst_sz)
787 {
788 	return ldns_b32_pton_base(src, src_sz, dst, dst_sz, true, true);
789 }
790 
791 #endif /* ! HAVE_B32_PTON */
792 
793