diff options
Diffstat (limited to '')
| -rw-r--r-- | src/libdnssec/shared/hex.c | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/src/libdnssec/shared/hex.c b/src/libdnssec/shared/hex.c new file mode 100644 index 0000000..03c1491 --- /dev/null +++ b/src/libdnssec/shared/hex.c @@ -0,0 +1,167 @@ +/* Copyright (C) 2018 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz> + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. +*/ + +#include <assert.h> +#include <string.h> +#include <stdbool.h> + +#include "libdnssec/binary.h" +#include "libdnssec/error.h" + +#include "contrib/ctype.h" + +/* -- binary to hex -------------------------------------------------------- */ + +static const char BIN_TO_HEX[] = { '0', '1', '2', '3', '4', '5', '6', '7', + '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' }; + +int bin_to_hex_static(const dnssec_binary_t *bin, dnssec_binary_t *hex) +{ + if (!bin || !hex) { + return DNSSEC_EINVAL; + } + + if (bin->size * 2 != hex->size) { + return DNSSEC_EINVAL; + } + + for (size_t i = 0; i < bin->size; i++) { + hex->data[2*i] = BIN_TO_HEX[bin->data[i] >> 4]; + hex->data[2*i+1] = BIN_TO_HEX[bin->data[i] & 0x0f]; + } + + return DNSSEC_EOK; +} + +int bin_to_hex(const dnssec_binary_t *bin, char **hex_ptr) +{ + if (!bin || !hex_ptr) { + return DNSSEC_EINVAL; + } + + size_t hex_size = bin->size * 2; + char *hex = malloc(hex_size + 1); + if (!hex) { + return DNSSEC_ENOMEM; + } + + dnssec_binary_t hex_bin = { .data = (uint8_t *)hex, .size = hex_size }; + bin_to_hex_static(bin, &hex_bin); + hex[hex_size] = '\0'; + + *hex_ptr = hex; + + return DNSSEC_EOK; +} + +/* -- hex to binary -------------------------------------------------------- */ + +/*! + * Convert HEX character to numeric value (assumes valid and lowercase input). + */ +static uint8_t hex_to_number(const char hex) +{ + if (hex >= '0' && hex <= '9') { + return hex - '0'; + } else if (hex >= 'a' && hex <= 'f') { + return hex - 'a' + 10; + } else { + assert(hex >= 'A' && hex <= 'F'); + return hex - 'A' + 10; + } +} + +/*! + * Check if the input string has valid size and contains valid characters. + */ +static bool hex_valid_input(const dnssec_binary_t *hex) +{ + assert(hex); + + if (hex->size % 2 != 0) { + return false; + } + + for (int i = 0; i < hex->size; i++) { + if (!is_xdigit(hex->data[i])) { + return false; + } + } + + return true; +} + +/*! + * Perform hex to bin conversion without checking the validity. + */ +static void hex_to_bin_convert(const dnssec_binary_t *hex, dnssec_binary_t *bin) +{ + assert(hex); + assert(bin); + + for (size_t i = 0; i < bin->size; i++) { + uint8_t high = hex_to_number(hex->data[2 * i]); + uint8_t low = hex_to_number(hex->data[2 * i + 1]); + bin->data[i] = high << 4 | low; + } +} + +int hex_to_bin_static(const dnssec_binary_t *hex, dnssec_binary_t *bin) +{ + if (!hex || !bin) { + return DNSSEC_EINVAL; + } + + if (hex->size / 2 != bin->size) { + return DNSSEC_EINVAL; + } + + if (!hex_valid_input(hex)) { + return DNSSEC_MALFORMED_DATA; + } + + hex_to_bin_convert(hex, bin); + + return DNSSEC_EOK; +} + +int hex_to_bin(const char *hex_str, dnssec_binary_t *bin) +{ + if (!hex_str || !bin) { + return DNSSEC_EINVAL; + } + + dnssec_binary_t hex = { .data = (uint8_t *)hex_str, .size = strlen(hex_str) }; + if (!hex_valid_input(&hex)) { + return DNSSEC_MALFORMED_DATA; + } + + size_t bin_size = hex.size / 2; + if (bin_size == 0) { + bin->size = 0; + bin->data = NULL; + return DNSSEC_EOK; + } + + int result = dnssec_binary_alloc(bin, bin_size); + if (result != DNSSEC_EOK) { + return result; + } + + hex_to_bin_static(&hex, bin); + + return DNSSEC_EOK; +} |