util.c

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/*
 * 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_arithmetics_time(int32_t time, time_t now)
{
        /* Casting due to https://github.com/NLnetLabs/ldns/issues/71 */
        int32_t offset = (int32_t) ((uint32_t) time - (uint32_t) now);
        return (int64_t) now + offset;
}
 
struct tm *
ldns_serial_arithmetics_gmtime_r(int32_t time, time_t now, struct tm *result)
{
#if SIZEOF_TIME_T <= 4
        int64_t secs_since_epoch = ldns_serial_arithmetics_time(time, now);
        return  ldns_gmtime64_r(secs_since_epoch, result);
#else
        time_t  secs_since_epoch = ldns_serial_arithmetics_time(time, now);
        return  gmtime_r(&secs_since_epoch, result);
#endif
}
 
#ifdef ldns_serial_arithmitics_gmtime_r
#undef ldns_serial_arithmitics_gmtime_r
#endif
/* alias function because of previously used wrong spelling */
struct tm *
ldns_serial_arithmitics_gmtime_r(int32_t time, time_t now, struct tm *result)
{
        return ldns_serial_arithmetics_gmtime_r(time, now, result);
}
 
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(unsigned 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;
}
 
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 ;
                /* fallthrough */
        case 3: dst[4] = b32[(src[2] & 0x0f) << 1 | c];
 
                /* ........ .......3 3333.... ........ ........ */
                         c =  src[2]         >> 4 ;
                /* fallthrough */
        case 2: dst[3] = b32[(src[1] & 0x01) << 4 | c];
 
                /* ........ ..22222. ........ ........ ........ */
                dst[2] = b32[(src[1] & 0x3e) >> 1];
 
                /* .....111 11...... ........ ........ ........ */
                         c =  src[1]         >> 6 ;
                /* fallthrough */
        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] = '=';
                                /* fallthrough */
                        case 2: dst[4] = '=';
                                /* fallthrough */
                        case 3: dst[5] = '=';
                                dst[6] = '=';
                                /* fallthrough */
                        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;
                        /* fallthrough */
 
                case 5: /* ........ ........ ....4444 4....... ........ */
                        /* ........ .......3 3333.... ........ ........ */
                        dst[2] = buf[3] << 4 | buf[4] >> 1;
                        /* fallthrough */
 
                case 4: /* ........ .......3 3333.... ........ ........ */
                        /* ........ ..22222. ........ ........ ........ */
                        /* .....111 11...... ........ ........ ........ */
                        dst[1] = buf[1] << 6 | buf[2] << 1 | buf[3] >> 4;
                        /* fallthrough */
 
                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 */