xref: /freebsd/contrib/ldns/util.c (revision 7899f917b1c0ea178f1d2be0cfb452086d079d23)
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 *ldns_serial_arithmitics_gmtime_r(int32_t, time_t, struct tm *);
320 struct tm *
321 ldns_serial_arithmitics_gmtime_r(int32_t time, time_t now, struct tm *result)
322 {
323 	return ldns_serial_arithmetics_gmtime_r(time, now, result);
324 }
325 
326 /**
327  * Init the random source
328  * applications should call this if they need entropy data within ldns
329  * If openSSL is available, it is automatically seeded from /dev/urandom
330  * or /dev/random
331  *
332  * If you need more entropy, or have no openssl available, this function
333  * MUST be called at the start of the program
334  *
335  * If openssl *is* available, this function just adds more entropy
336  **/
337 int
338 ldns_init_random(FILE *fd, unsigned int size)
339 {
340 	/* if fp is given, seed srandom with data from file
341 	   otherwise use /dev/urandom */
342 	FILE *rand_f;
343 	uint8_t *seed;
344 	size_t read = 0;
345 	unsigned int seed_i;
346 	struct timeval tv;
347 
348 	/* we'll need at least sizeof(unsigned int) bytes for the
349 	   standard prng seed */
350 	if (size < (unsigned int) sizeof(seed_i)){
351 		size = (unsigned int) sizeof(seed_i);
352 	}
353 
354 	seed = LDNS_XMALLOC(uint8_t, size);
355         if(!seed) {
356 		return 1;
357         }
358 
359 	if (!fd) {
360 		if ((rand_f = fopen("/dev/urandom", "r")) == NULL) {
361 			/* no readable /dev/urandom, try /dev/random */
362 			if ((rand_f = fopen("/dev/random", "r")) == NULL) {
363 				/* no readable /dev/random either, and no entropy
364 				   source given. we'll have to improvise */
365 				for (read = 0; read < size; read++) {
366 					gettimeofday(&tv, NULL);
367 					seed[read] = (uint8_t) (tv.tv_usec % 256);
368 				}
369 			} else {
370 				read = fread(seed, 1, size, rand_f);
371 			}
372 		} else {
373 			read = fread(seed, 1, size, rand_f);
374 		}
375 	} else {
376 		rand_f = fd;
377 		read = fread(seed, 1, size, rand_f);
378 	}
379 
380 	if (read < size) {
381 		LDNS_FREE(seed);
382 		if (!fd) fclose(rand_f);
383 		return 1;
384 	} else {
385 #ifdef HAVE_SSL
386 		/* Seed the OpenSSL prng (most systems have it seeded
387 		   automatically, in that case this call just adds entropy */
388 		RAND_seed(seed, (int) size);
389 #else
390 		/* Seed the standard prng, only uses the first
391 		 * unsigned sizeof(unsigned int) bytes found in the entropy pool
392 		 */
393 		memcpy(&seed_i, seed, sizeof(seed_i));
394 		srandom(seed_i);
395 #endif
396 		LDNS_FREE(seed);
397 	}
398 
399 	if (!fd) {
400                 if (rand_f) fclose(rand_f);
401 	}
402 
403 	return 0;
404 }
405 
406 /**
407  * Get random number.
408  *
409  */
410 uint16_t
411 ldns_get_random(void)
412 {
413         uint16_t rid = 0;
414 #ifdef HAVE_SSL
415         if (RAND_bytes((unsigned char*)&rid, 2) != 1) {
416                 rid = (uint16_t) random();
417         }
418 #else
419         rid = (uint16_t) random();
420 #endif
421 	return rid;
422 }
423 
424 /*
425  * BubbleBabble code taken from OpenSSH
426  * Copyright (c) 2001 Carsten Raskgaard.  All rights reserved.
427  */
428 char *
429 ldns_bubblebabble(uint8_t *data, size_t len)
430 {
431 	char vowels[] = { 'a', 'e', 'i', 'o', 'u', 'y' };
432 	char consonants[] = { 'b', 'c', 'd', 'f', 'g', 'h', 'k', 'l', 'm',
433 	    'n', 'p', 'r', 's', 't', 'v', 'z', 'x' };
434 	size_t i, j = 0, rounds, seed = 1;
435 	char *retval;
436 
437 	rounds = (len / 2) + 1;
438 	retval = LDNS_XMALLOC(char, rounds * 6);
439 	if(!retval) return NULL;
440 	retval[j++] = 'x';
441 	for (i = 0; i < rounds; i++) {
442 		size_t idx0, idx1, idx2, idx3, idx4;
443 		if ((i + 1 < rounds) || (len % 2 != 0)) {
444 			idx0 = (((((size_t)(data[2 * i])) >> 6) & 3) +
445 			    seed) % 6;
446 			idx1 = (((size_t)(data[2 * i])) >> 2) & 15;
447 			idx2 = ((((size_t)(data[2 * i])) & 3) +
448 			    (seed / 6)) % 6;
449 			retval[j++] = vowels[idx0];
450 			retval[j++] = consonants[idx1];
451 			retval[j++] = vowels[idx2];
452 			if ((i + 1) < rounds) {
453 				idx3 = (((size_t)(data[(2 * i) + 1])) >> 4) & 15;
454 				idx4 = (((size_t)(data[(2 * i) + 1]))) & 15;
455 				retval[j++] = consonants[idx3];
456 				retval[j++] = '-';
457 				retval[j++] = consonants[idx4];
458 				seed = ((seed * 5) +
459 				    ((((size_t)(data[2 * i])) * 7) +
460 				    ((size_t)(data[(2 * i) + 1])))) % 36;
461 			}
462 		} else {
463 			idx0 = seed % 6;
464 			idx1 = 16;
465 			idx2 = seed / 6;
466 			retval[j++] = vowels[idx0];
467 			retval[j++] = consonants[idx1];
468 			retval[j++] = vowels[idx2];
469 		}
470 	}
471 	retval[j++] = 'x';
472 	retval[j++] = '\0';
473 	return retval;
474 }
475 
476 /*
477  * For backwards compatibility, because we have always exported this symbol.
478  */
479 #ifdef HAVE_B64_NTOP
480 int ldns_b64_ntop(const uint8_t* src, size_t srclength,
481 		char *target, size_t targsize);
482 {
483 	return b64_ntop(src, srclength, target, targsize);
484 }
485 #endif
486 
487 /*
488  * For backwards compatibility, because we have always exported this symbol.
489  */
490 #ifdef HAVE_B64_PTON
491 int ldns_b64_pton(const char* src, uint8_t *target, size_t targsize)
492 {
493 	return b64_pton(src, target, targsize);
494 }
495 #endif
496 
497 
498 static int
499 ldns_b32_ntop_base(const uint8_t* src, size_t src_sz,
500 		char* dst, size_t dst_sz,
501 		bool extended_hex, bool add_padding)
502 {
503 	size_t ret_sz;
504 	const char* b32 = extended_hex ? "0123456789abcdefghijklmnopqrstuv"
505 	                               : "abcdefghijklmnopqrstuvwxyz234567";
506 
507 	size_t c = 0; /* c is used to carry partial base32 character over
508 	               * byte boundaries for sizes with a remainder.
509 		       * (i.e. src_sz % 5 != 0)
510 		       */
511 
512 	ret_sz = add_padding ? ldns_b32_ntop_calculate_size(src_sz)
513 	                     : ldns_b32_ntop_calculate_size_no_padding(src_sz);
514 
515 	/* Do we have enough space? */
516 	if (dst_sz < ret_sz + 1)
517 		return -1;
518 
519 	/* We know the size; terminate the string */
520 	dst[ret_sz] = '\0';
521 
522 	/* First process all chunks of five */
523 	while (src_sz >= 5) {
524 		/* 00000... ........ ........ ........ ........ */
525 		dst[0] = b32[(src[0]       ) >> 3];
526 
527 		/* .....111 11...... ........ ........ ........ */
528 		dst[1] = b32[(src[0] & 0x07) << 2 | src[1] >> 6];
529 
530 		/* ........ ..22222. ........ ........ ........ */
531 		dst[2] = b32[(src[1] & 0x3e) >> 1];
532 
533 		/* ........ .......3 3333.... ........ ........ */
534 		dst[3] = b32[(src[1] & 0x01) << 4 | src[2] >> 4];
535 
536 		/* ........ ........ ....4444 4....... ........ */
537 		dst[4] = b32[(src[2] & 0x0f) << 1 | src[3] >> 7];
538 
539 		/* ........ ........ ........ .55555.. ........ */
540 		dst[5] = b32[(src[3] & 0x7c) >> 2];
541 
542 		/* ........ ........ ........ ......66 666..... */
543 		dst[6] = b32[(src[3] & 0x03) << 3 | src[4] >> 5];
544 
545 		/* ........ ........ ........ ........ ...77777 */
546 		dst[7] = b32[(src[4] & 0x1f)     ];
547 
548 		src_sz -= 5;
549 		src    += 5;
550 		dst    += 8;
551 	}
552 	/* Process what remains */
553 	switch (src_sz) {
554 	case 4: /* ........ ........ ........ ......66 666..... */
555 		dst[6] = b32[(src[3] & 0x03) << 3];
556 
557 		/* ........ ........ ........ .55555.. ........ */
558 		dst[5] = b32[(src[3] & 0x7c) >> 2];
559 
560 		/* ........ ........ ....4444 4....... ........ */
561 		         c =  src[3]         >> 7 ;
562 		/* fallthrough */
563 	case 3: dst[4] = b32[(src[2] & 0x0f) << 1 | c];
564 
565 		/* ........ .......3 3333.... ........ ........ */
566 			 c =  src[2]         >> 4 ;
567 		/* fallthrough */
568 	case 2:	dst[3] = b32[(src[1] & 0x01) << 4 | c];
569 
570 		/* ........ ..22222. ........ ........ ........ */
571 		dst[2] = b32[(src[1] & 0x3e) >> 1];
572 
573 		/* .....111 11...... ........ ........ ........ */
574 	                 c =  src[1]         >> 6 ;
575 		/* fallthrough */
576 	case 1:	dst[1] = b32[(src[0] & 0x07) << 2 | c];
577 
578 		/* 00000... ........ ........ ........ ........ */
579 		dst[0] = b32[ src[0]         >> 3];
580 	}
581 	/* Add padding */
582 	if (add_padding) {
583 		switch (src_sz) {
584 			case 1: dst[2] = '=';
585 				dst[3] = '=';
586 				/* fallthrough */
587 			case 2: dst[4] = '=';
588 				/* fallthrough */
589 			case 3: dst[5] = '=';
590 				dst[6] = '=';
591 				/* fallthrough */
592 			case 4: dst[7] = '=';
593 		}
594 	}
595 	return (int)ret_sz;
596 }
597 
598 int
599 ldns_b32_ntop(const uint8_t* src, size_t src_sz, char* dst, size_t dst_sz)
600 {
601 	return ldns_b32_ntop_base(src, src_sz, dst, dst_sz, false, true);
602 }
603 
604 int
605 ldns_b32_ntop_extended_hex(const uint8_t* src, size_t src_sz,
606 		char* dst, size_t dst_sz)
607 {
608 	return ldns_b32_ntop_base(src, src_sz, dst, dst_sz, true, true);
609 }
610 
611 #ifndef HAVE_B32_NTOP
612 
613 int
614 b32_ntop(const uint8_t* src, size_t src_sz, char* dst, size_t dst_sz)
615 {
616 	return ldns_b32_ntop_base(src, src_sz, dst, dst_sz, false, true);
617 }
618 
619 int
620 b32_ntop_extended_hex(const uint8_t* src, size_t src_sz,
621 		char* dst, size_t dst_sz)
622 {
623 	return ldns_b32_ntop_base(src, src_sz, dst, dst_sz, true, true);
624 }
625 
626 #endif /* ! HAVE_B32_NTOP */
627 
628 static int
629 ldns_b32_pton_base(const char* src, size_t src_sz,
630 		uint8_t* dst, size_t dst_sz,
631 		bool extended_hex, bool check_padding)
632 {
633 	size_t i = 0;
634 	char ch = '\0';
635 	uint8_t buf[8];
636 	uint8_t* start = dst;
637 
638 	while (src_sz) {
639 		/* Collect 8 characters in buf (if possible) */
640 		for (i = 0; i < 8; i++) {
641 
642 			do {
643 				ch = *src++;
644 				--src_sz;
645 
646 			} while (isspace((unsigned char)ch) && src_sz > 0);
647 
648 			if (ch == '=' || ch == '\0')
649 				break;
650 
651 			else if (extended_hex)
652 
653 				if (ch >= '0' && ch <= '9')
654 					buf[i] = (uint8_t)ch - '0';
655 				else if (ch >= 'a' && ch <= 'v')
656 					buf[i] = (uint8_t)ch - 'a' + 10;
657 				else if (ch >= 'A' && ch <= 'V')
658 					buf[i] = (uint8_t)ch - 'A' + 10;
659 				else
660 					return -1;
661 
662 			else if (ch >= 'a' && ch <= 'z')
663 				buf[i] = (uint8_t)ch - 'a';
664 			else if (ch >= 'A' && ch <= 'Z')
665 				buf[i] = (uint8_t)ch - 'A';
666 			else if (ch >= '2' && ch <= '7')
667 				buf[i] = (uint8_t)ch - '2' + 26;
668 			else
669 				return -1;
670 		}
671 		/* Less that 8 characters. We're done. */
672 		if (i < 8)
673 			break;
674 
675 		/* Enough space available at the destination? */
676 		if (dst_sz < 5)
677 			return -1;
678 
679 		/* 00000... ........ ........ ........ ........ */
680 		/* .....111 11...... ........ ........ ........ */
681 		dst[0] = buf[0] << 3 | buf[1] >> 2;
682 
683 		/* .....111 11...... ........ ........ ........ */
684 		/* ........ ..22222. ........ ........ ........ */
685 		/* ........ .......3 3333.... ........ ........ */
686 		dst[1] = buf[1] << 6 | buf[2] << 1 | buf[3] >> 4;
687 
688 		/* ........ .......3 3333.... ........ ........ */
689 		/* ........ ........ ....4444 4....... ........ */
690 		dst[2] = buf[3] << 4 | buf[4] >> 1;
691 
692 		/* ........ ........ ....4444 4....... ........ */
693 		/* ........ ........ ........ .55555.. ........ */
694 		/* ........ ........ ........ ......66 666..... */
695 		dst[3] = buf[4] << 7 | buf[5] << 2 | buf[6] >> 3;
696 
697 		/* ........ ........ ........ ......66 666..... */
698 		/* ........ ........ ........ ........ ...77777 */
699 		dst[4] = buf[6] << 5 | buf[7];
700 
701 		dst += 5;
702 		dst_sz -= 5;
703 	}
704 	/* Not ending on a eight byte boundary? */
705 	if (i > 0 && i < 8) {
706 
707 		/* Enough space available at the destination? */
708 		if (dst_sz < (i + 1) / 2)
709 			return -1;
710 
711 		switch (i) {
712 		case 7: /* ........ ........ ........ ......66 666..... */
713 			/* ........ ........ ........ .55555.. ........ */
714 			/* ........ ........ ....4444 4....... ........ */
715 			dst[3] = buf[4] << 7 | buf[5] << 2 | buf[6] >> 3;
716 			/* fallthrough */
717 
718 		case 5: /* ........ ........ ....4444 4....... ........ */
719 			/* ........ .......3 3333.... ........ ........ */
720 			dst[2] = buf[3] << 4 | buf[4] >> 1;
721 			/* fallthrough */
722 
723 		case 4: /* ........ .......3 3333.... ........ ........ */
724 			/* ........ ..22222. ........ ........ ........ */
725 			/* .....111 11...... ........ ........ ........ */
726 			dst[1] = buf[1] << 6 | buf[2] << 1 | buf[3] >> 4;
727 			/* fallthrough */
728 
729 		case 2: /* .....111 11...... ........ ........ ........ */
730 			/* 00000... ........ ........ ........ ........ */
731 			dst[0] = buf[0] << 3 | buf[1] >> 2;
732 
733 			break;
734 
735 		default:
736 			return -1;
737 		}
738 		dst += (i + 1) / 2;
739 
740 		if (check_padding) {
741 			/* Check remaining padding characters */
742 			if (ch != '=')
743 				return -1;
744 
745 			/* One down, 8 - i - 1 more to come... */
746 			for (i = 8 - i - 1; i > 0; i--) {
747 
748 				do {
749 					if (src_sz == 0)
750 						return -1;
751 					ch = *src++;
752 					src_sz--;
753 
754 				} while (isspace((unsigned char)ch));
755 
756 				if (ch != '=')
757 					return -1;
758 			}
759 		}
760 	}
761 	return dst - start;
762 }
763 
764 int
765 ldns_b32_pton(const char* src, size_t src_sz, uint8_t* dst, size_t dst_sz)
766 {
767 	return ldns_b32_pton_base(src, src_sz, dst, dst_sz, false, true);
768 }
769 
770 int
771 ldns_b32_pton_extended_hex(const char* src, size_t src_sz,
772 		uint8_t* dst, size_t dst_sz)
773 {
774 	return ldns_b32_pton_base(src, src_sz, dst, dst_sz, true, true);
775 }
776 
777 #ifndef HAVE_B32_PTON
778 
779 int
780 b32_pton(const char* src, size_t src_sz, uint8_t* dst, size_t dst_sz)
781 {
782 	return ldns_b32_pton_base(src, src_sz, dst, dst_sz, false, true);
783 }
784 
785 int
786 b32_pton_extended_hex(const char* src, size_t src_sz,
787 		uint8_t* dst, size_t dst_sz)
788 {
789 	return ldns_b32_pton_base(src, src_sz, dst, dst_sz, true, true);
790 }
791 
792 #endif /* ! HAVE_B32_PTON */
793 
794