Training courses

Kernel and Embedded Linux

Bootlin training courses

Embedded Linux, kernel,
Yocto Project, Buildroot, real-time,
graphics, boot time, debugging...

Bootlin logo

Elixir Cross Referencer

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
/*
 * util.c
 *
 * some general memory functions
 *
 * a Net::DNS like library for C
 *
 * (c) NLnet Labs, 2004-2006
 *
 * See the file LICENSE for the license
 */

#include <ldns/config.h>

#include <ldns/rdata.h>
#include <ldns/rr.h>
#include <ldns/util.h>
#include <strings.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/time.h>
#include <time.h>
#include <ctype.h>

#ifdef HAVE_SSL
#include <openssl/rand.h>
#endif

ldns_lookup_table *
ldns_lookup_by_name(ldns_lookup_table *table, const char *name)
{
	while (table->name != NULL) {
		if (strcasecmp(name, table->name) == 0)
			return table;
		table++;
	}
	return NULL;
}

ldns_lookup_table *
ldns_lookup_by_id(ldns_lookup_table *table, int id)
{
	while (table->name != NULL) {
		if (table->id == id)
			return table;
		table++;
	}
	return NULL;
}

int
ldns_get_bit(uint8_t bits[], size_t index)
{
	/*
	 * The bits are counted from left to right, so bit #0 is the
	 * left most bit.
	 */
	return (int) (bits[index / 8] & (1 << (7 - index % 8)));
}

int
ldns_get_bit_r(uint8_t bits[], size_t index)
{
	/*
	 * The bits are counted from right to left, so bit #0 is the
	 * right most bit.
	 */
	return (int) bits[index / 8] & (1 << (index % 8));
}

void
ldns_set_bit(uint8_t *byte, int bit_nr, bool value)
{
	/*
	 * The bits are counted from right to left, so bit #0 is the
	 * right most bit.
	 */
	if (bit_nr >= 0 && bit_nr < 8) {
		if (value) {
			*byte = *byte | (0x01 << bit_nr);
		} else {
			*byte = *byte & ~(0x01 << bit_nr);
		}
	}
}

int
ldns_hexdigit_to_int(char ch)
{
	switch (ch) {
	case '0': return 0;
	case '1': return 1;
	case '2': return 2;
	case '3': return 3;
	case '4': return 4;
	case '5': return 5;
	case '6': return 6;
	case '7': return 7;
	case '8': return 8;
	case '9': return 9;
	case 'a': case 'A': return 10;
	case 'b': case 'B': return 11;
	case 'c': case 'C': return 12;
	case 'd': case 'D': return 13;
	case 'e': case 'E': return 14;
	case 'f': case 'F': return 15;
	default:
		return -1;
	}
}

char
ldns_int_to_hexdigit(int i)
{
	switch (i) {
	case 0: return '0';
	case 1: return '1';
	case 2: return '2';
	case 3: return '3';
	case 4: return '4';
	case 5: return '5';
	case 6: return '6';
	case 7: return '7';
	case 8: return '8';
	case 9: return '9';
	case 10: return 'a';
	case 11: return 'b';
	case 12: return 'c';
	case 13: return 'd';
	case 14: return 'e';
	case 15: return 'f';
	default:
		abort();
	}
}

int
ldns_hexstring_to_data(uint8_t *data, const char *str)
{
	size_t i;

	if (!str || !data) {
		return -1;
	}

	if (strlen(str) % 2 != 0) {
		return -2;
	}

	for (i = 0; i < strlen(str) / 2; i++) {
		data[i] =
			16 * (uint8_t) ldns_hexdigit_to_int(str[i*2]) +
			(uint8_t) ldns_hexdigit_to_int(str[i*2 + 1]);
	}

	return (int) i;
}

const char *
ldns_version(void)
{
	return (char*)LDNS_VERSION;
}

/* Number of days per month (except for February in leap years). */
static const int mdays[] = {
	31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};

#define LDNS_MOD(x,y) (((x) % (y) < 0) ? ((x) % (y) + (y)) : ((x) % (y)))
#define LDNS_DIV(x,y) (((x) % (y) < 0) ? ((x) / (y) -  1 ) : ((x) / (y)))

static int
is_leap_year(int year)
{
	return LDNS_MOD(year,   4) == 0 && (LDNS_MOD(year, 100) != 0 
	    || LDNS_MOD(year, 400) == 0);
}

static int
leap_days(int y1, int y2)
{
	--y1;
	--y2;
	return (LDNS_DIV(y2,   4) - LDNS_DIV(y1,   4)) - 
	       (LDNS_DIV(y2, 100) - LDNS_DIV(y1, 100)) +
	       (LDNS_DIV(y2, 400) - LDNS_DIV(y1, 400));
}

/*
 * Code adapted from Python 2.4.1 sources (Lib/calendar.py).
 */
time_t
ldns_mktime_from_utc(const struct tm *tm)
{
	int year = 1900 + tm->tm_year;
	time_t days = 365 * ((time_t) year - 1970) + leap_days(1970, year);
	time_t hours;
	time_t minutes;
	time_t seconds;
	int i;

	for (i = 0; i < tm->tm_mon; ++i) {
		days += mdays[i];
	}
	if (tm->tm_mon > 1 && is_leap_year(year)) {
		++days;
	}
	days += tm->tm_mday - 1;

	hours = days * 24 + tm->tm_hour;
	minutes = hours * 60 + tm->tm_min;
	seconds = minutes * 60 + tm->tm_sec;

	return seconds;
}

time_t
mktime_from_utc(const struct tm *tm)
{
	return ldns_mktime_from_utc(tm);
}

#if SIZEOF_TIME_T <= 4

static void
ldns_year_and_yday_from_days_since_epoch(int64_t days, struct tm *result)
{
	int year = 1970;
	int new_year;

	while (days < 0 || days >= (int64_t) (is_leap_year(year) ? 366 : 365)) {
		new_year = year + (int) LDNS_DIV(days, 365);
		days -= (new_year - year) * 365;
		days -= leap_days(year, new_year);
		year  = new_year;
	}
	result->tm_year = year;
	result->tm_yday = (int) days;
}

/* Number of days per month in a leap year. */
static const int leap_year_mdays[] = {
	31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};

static void
ldns_mon_and_mday_from_year_and_yday(struct tm *result)
{
	int idays = result->tm_yday;
	const int *mon_lengths = is_leap_year(result->tm_year) ? 
					leap_year_mdays : mdays;

	result->tm_mon = 0;
	while  (idays >= mon_lengths[result->tm_mon]) {
		idays -= mon_lengths[result->tm_mon++];
	}
	result->tm_mday = idays + 1;
}

static void
ldns_wday_from_year_and_yday(struct tm *result)
{
	result->tm_wday = 4 /* 1-1-1970 was a thursday */
			+ LDNS_MOD((result->tm_year - 1970), 7) * LDNS_MOD(365, 7)
			+ leap_days(1970, result->tm_year)
			+ result->tm_yday;
	result->tm_wday = LDNS_MOD(result->tm_wday, 7);
	if (result->tm_wday < 0) {
		result->tm_wday += 7;
	}
}

static struct tm *
ldns_gmtime64_r(int64_t clock, struct tm *result)
{
	result->tm_isdst = 0;
	result->tm_sec   = (int) LDNS_MOD(clock, 60);
	clock            =       LDNS_DIV(clock, 60);
	result->tm_min   = (int) LDNS_MOD(clock, 60);
	clock            =       LDNS_DIV(clock, 60);
	result->tm_hour  = (int) LDNS_MOD(clock, 24);
	clock            =       LDNS_DIV(clock, 24);

	ldns_year_and_yday_from_days_since_epoch(clock, result);
	ldns_mon_and_mday_from_year_and_yday(result);
	ldns_wday_from_year_and_yday(result);
	result->tm_year -= 1900;

	return result;
}

#endif /* SIZEOF_TIME_T <= 4 */

static int64_t
ldns_serial_arithmitics_time(int32_t time, time_t now)
{
	int32_t offset = time - (int32_t) now;
	return (int64_t) now + offset;
}


struct tm *
ldns_serial_arithmitics_gmtime_r(int32_t time, time_t now, struct tm *result)
{
#if SIZEOF_TIME_T <= 4
	int64_t secs_since_epoch = ldns_serial_arithmitics_time(time, now);
	return  ldns_gmtime64_r(secs_since_epoch, result);
#else
	time_t  secs_since_epoch = ldns_serial_arithmitics_time(time, now);
	return  gmtime_r(&secs_since_epoch, result);
#endif
}

/**
 * Init the random source
 * applications should call this if they need entropy data within ldns
 * If openSSL is available, it is automatically seeded from /dev/urandom
 * or /dev/random
 *
 * If you need more entropy, or have no openssl available, this function
 * MUST be called at the start of the program
 *
 * If openssl *is* available, this function just adds more entropy
 **/
int
ldns_init_random(FILE *fd, unsigned int size)
{
	/* if fp is given, seed srandom with data from file
	   otherwise use /dev/urandom */
	FILE *rand_f;
	uint8_t *seed;
	size_t read = 0;
	unsigned int seed_i;
	struct timeval tv;

	/* we'll need at least sizeof(unsigned int) bytes for the
	   standard prng seed */
	if (size < (unsigned int) sizeof(seed_i)){
		size = (unsigned int) sizeof(seed_i);
	}

	seed = LDNS_XMALLOC(uint8_t, size);
        if(!seed) {
		return 1;
        }

	if (!fd) {
		if ((rand_f = fopen("/dev/urandom", "r")) == NULL) {
			/* no readable /dev/urandom, try /dev/random */
			if ((rand_f = fopen("/dev/random", "r")) == NULL) {
				/* no readable /dev/random either, and no entropy
				   source given. we'll have to improvise */
				for (read = 0; read < size; read++) {
					gettimeofday(&tv, NULL);
					seed[read] = (uint8_t) (tv.tv_usec % 256);
				}
			} else {
				read = fread(seed, 1, size, rand_f);
			}
		} else {
			read = fread(seed, 1, size, rand_f);
		}
	} else {
		rand_f = fd;
		read = fread(seed, 1, size, rand_f);
	}

	if (read < size) {
		LDNS_FREE(seed);
		if (!fd) fclose(rand_f);
		return 1;
	} else {
#ifdef HAVE_SSL
		/* Seed the OpenSSL prng (most systems have it seeded
		   automatically, in that case this call just adds entropy */
		RAND_seed(seed, (int) size);
#else
		/* Seed the standard prng, only uses the first
		 * unsigned sizeof(unsiged int) bytes found in the entropy pool
		 */
		memcpy(&seed_i, seed, sizeof(seed_i));
		srandom(seed_i);
#endif
		LDNS_FREE(seed);
	}

	if (!fd) {
                if (rand_f) fclose(rand_f);
	}

	return 0;
}

/**
 * Get random number.
 *
 */
uint16_t
ldns_get_random(void)
{
        uint16_t rid = 0;
#ifdef HAVE_SSL
        if (RAND_bytes((unsigned char*)&rid, 2) != 1) {
                rid = (uint16_t) random();
        }
#else
        rid = (uint16_t) random();
#endif
	return rid;
}

/*
 * BubbleBabble code taken from OpenSSH
 * Copyright (c) 2001 Carsten Raskgaard.  All rights reserved.
 */
char *
ldns_bubblebabble(uint8_t *data, size_t len)
{
	char vowels[] = { 'a', 'e', 'i', 'o', 'u', 'y' };
	char consonants[] = { 'b', 'c', 'd', 'f', 'g', 'h', 'k', 'l', 'm',
	    'n', 'p', 'r', 's', 't', 'v', 'z', 'x' };
	size_t i, j = 0, rounds, seed = 1;
	char *retval;

	rounds = (len / 2) + 1;
	retval = LDNS_XMALLOC(char, rounds * 6);
	if(!retval) return NULL;
	retval[j++] = 'x';
	for (i = 0; i < rounds; i++) {
		size_t idx0, idx1, idx2, idx3, idx4;
		if ((i + 1 < rounds) || (len % 2 != 0)) {
			idx0 = (((((size_t)(data[2 * i])) >> 6) & 3) +
			    seed) % 6;
			idx1 = (((size_t)(data[2 * i])) >> 2) & 15;
			idx2 = ((((size_t)(data[2 * i])) & 3) +
			    (seed / 6)) % 6;
			retval[j++] = vowels[idx0];
			retval[j++] = consonants[idx1];
			retval[j++] = vowels[idx2];
			if ((i + 1) < rounds) {
				idx3 = (((size_t)(data[(2 * i) + 1])) >> 4) & 15;
				idx4 = (((size_t)(data[(2 * i) + 1]))) & 15;
				retval[j++] = consonants[idx3];
				retval[j++] = '-';
				retval[j++] = consonants[idx4];
				seed = ((seed * 5) +
				    ((((size_t)(data[2 * i])) * 7) +
				    ((size_t)(data[(2 * i) + 1])))) % 36;
			}
		} else {
			idx0 = seed % 6;
			idx1 = 16;
			idx2 = seed / 6;
			retval[j++] = vowels[idx0];
			retval[j++] = consonants[idx1];
			retval[j++] = vowels[idx2];
		}
	}
	retval[j++] = 'x';
	retval[j++] = '\0';
	return retval;
}

/*
 * For backwards compatibility, because we have always exported this symbol.
 */
#ifdef HAVE_B64_NTOP
int ldns_b64_ntop(const uint8_t* src, size_t srclength,
		char *target, size_t targsize);
{
	return b64_ntop(src, srclength, target, targsize);
}
#endif

/*
 * For backwards compatibility, because we have always exported this symbol.
 */
#ifdef HAVE_B64_PTON
int ldns_b64_pton(const char* src, uint8_t *target, size_t targsize)
{
	return b64_pton(src, target, targsize);
}
#endif


static int
ldns_b32_ntop_base(const uint8_t* src, size_t src_sz,
		char* dst, size_t dst_sz,
		bool extended_hex, bool add_padding)
{
	size_t ret_sz;
	const char* b32 = extended_hex ? "0123456789abcdefghijklmnopqrstuv"
	                               : "abcdefghijklmnopqrstuvwxyz234567";

	size_t c = 0; /* c is used to carry partial base32 character over 
	               * byte boundaries for sizes with a remainder.
		       * (i.e. src_sz % 5 != 0)
		       */

	ret_sz = add_padding ? ldns_b32_ntop_calculate_size(src_sz)
	                     : ldns_b32_ntop_calculate_size_no_padding(src_sz);
	
	/* Do we have enough space? */
	if (dst_sz < ret_sz + 1)
		return -1;

	/* We know the size; terminate the string */
	dst[ret_sz] = '\0';

	/* First process all chunks of five */
	while (src_sz >= 5) {
		/* 00000... ........ ........ ........ ........ */
		dst[0] = b32[(src[0]       ) >> 3];

		/* .....111 11...... ........ ........ ........ */
		dst[1] = b32[(src[0] & 0x07) << 2 | src[1] >> 6];

		/* ........ ..22222. ........ ........ ........ */
		dst[2] = b32[(src[1] & 0x3e) >> 1];

		/* ........ .......3 3333.... ........ ........ */
		dst[3] = b32[(src[1] & 0x01) << 4 | src[2] >> 4];

		/* ........ ........ ....4444 4....... ........ */
		dst[4] = b32[(src[2] & 0x0f) << 1 | src[3] >> 7];

		/* ........ ........ ........ .55555.. ........ */
		dst[5] = b32[(src[3] & 0x7c) >> 2];

		/* ........ ........ ........ ......66 666..... */
		dst[6] = b32[(src[3] & 0x03) << 3 | src[4] >> 5];

		/* ........ ........ ........ ........ ...77777 */
		dst[7] = b32[(src[4] & 0x1f)     ];

		src_sz -= 5;
		src    += 5;
		dst    += 8;
	}
	/* Process what remains */
	switch (src_sz) {
	case 4: /* ........ ........ ........ ......66 666..... */
		dst[6] = b32[(src[3] & 0x03) << 3];

		/* ........ ........ ........ .55555.. ........ */
		dst[5] = b32[(src[3] & 0x7c) >> 2];

		/* ........ ........ ....4444 4....... ........ */
		         c =  src[3]         >> 7 ;
	case 3: dst[4] = b32[(src[2] & 0x0f) << 1 | c];

		/* ........ .......3 3333.... ........ ........ */
			 c =  src[2]         >> 4 ;
	case 2:	dst[3] = b32[(src[1] & 0x01) << 4 | c];

		/* ........ ..22222. ........ ........ ........ */
		dst[2] = b32[(src[1] & 0x3e) >> 1];

		/* .....111 11...... ........ ........ ........ */
	                 c =  src[1]         >> 6 ;
	case 1:	dst[1] = b32[(src[0] & 0x07) << 2 | c];

		/* 00000... ........ ........ ........ ........ */
		dst[0] = b32[ src[0]         >> 3];
	}
	/* Add padding */
	if (add_padding) {
		switch (src_sz) {
			case 1: dst[2] = '=';
				dst[3] = '=';
			case 2: dst[4] = '=';
			case 3: dst[5] = '=';
				dst[6] = '=';
			case 4: dst[7] = '=';
		}
	}
	return (int)ret_sz;
}

int 
ldns_b32_ntop(const uint8_t* src, size_t src_sz, char* dst, size_t dst_sz)
{
	return ldns_b32_ntop_base(src, src_sz, dst, dst_sz, false, true);
}

int 
ldns_b32_ntop_extended_hex(const uint8_t* src, size_t src_sz,
		char* dst, size_t dst_sz)
{
	return ldns_b32_ntop_base(src, src_sz, dst, dst_sz, true, true);
}

#ifndef HAVE_B32_NTOP

int 
b32_ntop(const uint8_t* src, size_t src_sz, char* dst, size_t dst_sz)
{
	return ldns_b32_ntop_base(src, src_sz, dst, dst_sz, false, true);
}

int 
b32_ntop_extended_hex(const uint8_t* src, size_t src_sz,
		char* dst, size_t dst_sz)
{
	return ldns_b32_ntop_base(src, src_sz, dst, dst_sz, true, true);
}

#endif /* ! HAVE_B32_NTOP */

static int
ldns_b32_pton_base(const char* src, size_t src_sz,
		uint8_t* dst, size_t dst_sz,
		bool extended_hex, bool check_padding)
{
	size_t i = 0;
	char ch = '\0';
	uint8_t buf[8];
	uint8_t* start = dst;

	while (src_sz) {
		/* Collect 8 characters in buf (if possible) */
		for (i = 0; i < 8; i++) {

			do {
				ch = *src++;
				--src_sz;

			} while (isspace((unsigned char)ch) && src_sz > 0);

			if (ch == '=' || ch == '\0')
				break;

			else if (extended_hex)

				if (ch >= '0' && ch <= '9')
					buf[i] = (uint8_t)ch - '0';
				else if (ch >= 'a' && ch <= 'v')
					buf[i] = (uint8_t)ch - 'a' + 10;
				else if (ch >= 'A' && ch <= 'V')
					buf[i] = (uint8_t)ch - 'A' + 10;
				else
					return -1;

			else if (ch >= 'a' && ch <= 'z')
				buf[i] = (uint8_t)ch - 'a';
			else if (ch >= 'A' && ch <= 'Z')
				buf[i] = (uint8_t)ch - 'A';
			else if (ch >= '2' && ch <= '7')
				buf[i] = (uint8_t)ch - '2' + 26;
			else
				return -1;
		}
		/* Less that 8 characters. We're done. */
		if (i < 8)
			break;

		/* Enough space available at the destination? */
		if (dst_sz < 5)
			return -1;

		/* 00000... ........ ........ ........ ........ */
		/* .....111 11...... ........ ........ ........ */
		dst[0] = buf[0] << 3 | buf[1] >> 2;

		/* .....111 11...... ........ ........ ........ */
		/* ........ ..22222. ........ ........ ........ */
		/* ........ .......3 3333.... ........ ........ */
		dst[1] = buf[1] << 6 | buf[2] << 1 | buf[3] >> 4;

		/* ........ .......3 3333.... ........ ........ */
		/* ........ ........ ....4444 4....... ........ */
		dst[2] = buf[3] << 4 | buf[4] >> 1;

		/* ........ ........ ....4444 4....... ........ */
		/* ........ ........ ........ .55555.. ........ */
		/* ........ ........ ........ ......66 666..... */
		dst[3] = buf[4] << 7 | buf[5] << 2 | buf[6] >> 3;

		/* ........ ........ ........ ......66 666..... */
		/* ........ ........ ........ ........ ...77777 */
		dst[4] = buf[6] << 5 | buf[7];

		dst += 5;
		dst_sz -= 5;
	}
	/* Not ending on a eight byte boundary? */
	if (i > 0 && i < 8) {

		/* Enough space available at the destination? */
		if (dst_sz < (i + 1) / 2)
			return -1;

		switch (i) {
		case 7: /* ........ ........ ........ ......66 666..... */
			/* ........ ........ ........ .55555.. ........ */
			/* ........ ........ ....4444 4....... ........ */
			dst[3] = buf[4] << 7 | buf[5] << 2 | buf[6] >> 3;

		case 5: /* ........ ........ ....4444 4....... ........ */
			/* ........ .......3 3333.... ........ ........ */
			dst[2] = buf[3] << 4 | buf[4] >> 1;

		case 4: /* ........ .......3 3333.... ........ ........ */
			/* ........ ..22222. ........ ........ ........ */
			/* .....111 11...... ........ ........ ........ */
			dst[1] = buf[1] << 6 | buf[2] << 1 | buf[3] >> 4;

		case 2: /* .....111 11...... ........ ........ ........ */
			/* 00000... ........ ........ ........ ........ */
			dst[0] = buf[0] << 3 | buf[1] >> 2;

			break;

		default:
			return -1;
		}
		dst += (i + 1) / 2;

		if (check_padding) {
			/* Check remaining padding characters */
			if (ch != '=')
				return -1;

			/* One down, 8 - i - 1 more to come... */
			for (i = 8 - i - 1; i > 0; i--) {

				do {
					if (src_sz == 0)
						return -1;
					ch = *src++;
					src_sz--;

				} while (isspace((unsigned char)ch));

				if (ch != '=')
					return -1;
			}
		}
	}
	return dst - start;
}

int
ldns_b32_pton(const char* src, size_t src_sz, uint8_t* dst, size_t dst_sz)
{
	return ldns_b32_pton_base(src, src_sz, dst, dst_sz, false, true);
}

int
ldns_b32_pton_extended_hex(const char* src, size_t src_sz, 
		uint8_t* dst, size_t dst_sz)
{
	return ldns_b32_pton_base(src, src_sz, dst, dst_sz, true, true);
}

#ifndef HAVE_B32_PTON

int
b32_pton(const char* src, size_t src_sz, uint8_t* dst, size_t dst_sz)
{
	return ldns_b32_pton_base(src, src_sz, dst, dst_sz, false, true);
}

int
b32_pton_extended_hex(const char* src, size_t src_sz, 
		uint8_t* dst, size_t dst_sz)
{
	return ldns_b32_pton_base(src, src_sz, dst, dst_sz, true, true);
}

#endif /* ! HAVE_B32_PTON */