contrib/ldns/util.c

   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