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Diffstat (limited to 'src/libdnssec/nsec.h')
| -rw-r--r-- | src/libdnssec/nsec.h | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/src/libdnssec/nsec.h b/src/libdnssec/nsec.h new file mode 100644 index 0000000..ce69752 --- /dev/null +++ b/src/libdnssec/nsec.h @@ -0,0 +1,214 @@ +/* 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/>. +*/ +/*! + * \file + * + * \addtogroup nsec + * + * \brief NSEC bitmap and NSEC3 hash computation API. + * + * The module provides interface for computation of NSEC3 hashes and for + * construction of bit maps used in NSEC and NSEC3 records. + * + * Example of NSEC3 hash computation: + * + * ~~~~~ {.c} + * + * int result; + * + * // NSEC3 parameters for hashing + * nssec_nsec3_params_t params = { + * .algorithm = DNSSEC_NSEC3_ALGORITHM_SHA1, + * .flags = 0, + * .iterations = 10, + * .salt = { + * .size = 4, + * .data = (uint8_t *){ 0xc0, 0x1d, 0xca, 0xfe } + * } + * }; + * + * // domain name (in wire format) + * uint8_t *dname = "\0x08""knot-dns""\0x02""cz"; + * + * // resulting hash + * dnssec_binary_t hash = { 0 }; + * + * result = dnssec_nsec3_hash(&dname, ¶ms, &hash); + * if (result != DNSSEC_EOK) { + * return result; + * } + * + * assert(hash.size == 20); + * // hash.data contains binary data, which encoded in Base32 would be: + * // 7PTVGE7QV67EM61ROS9238P5RAKR2DM7 + * + * dnssec_binary_free(&hash); + * + * ~~~~~ + * + * Example of NSEC/NSEC3 bitmap construction. + * + * ~~~~~ {.c} + * + * int result; + * dnssec_nsec_bitmap_t *ctx; + * dnssec_binary_t bitmap; + * + * // create encoding context + * ctx = dnssec_nsec_bitmap_new(); + * if (ctx == NULL) { + * return KNOT_ENOMEM; + * } + * + * // add resource records into the bitmap + * dnssec_nsec_bitmap_add(ctx, 1); // A RR type + * dnssec_nsec_bitmap_add(ctx, 28); // AAAA RR type + * + * // allocate space for the encoded bitmap + * size_t size = dnssec_nsec_bitmap_size(ctx); + * result = dnssec_binary_alloc(&bitmap, size); + * if (result != DNSSEC_EOK) { + * dnssec_nsec_bitmap_free(ctx); + * return result; + * } + * + * // write the encoded bitmap and free the context + * dnssec_nsec_bitmap_write(ctx, &bitmap); + * dnssec_nsec_bitmap_free(ctx); + * + * // use the bitmap ... + * + * dnssec_binary_free(&bitmap); + * ~~~~~ + * + * @{ + */ + +#pragma once + +#include <stddef.h> +#include <stdint.h> +#include <stdbool.h> + +#include <libdnssec/binary.h> + +/*! + * DNSSEC NSEC3 algorithm numbers. + */ +typedef enum dnssec_nsec_algorithm { + DNSSEC_NSEC3_ALGORITHM_UNKNOWN = 0, + DNSSEC_NSEC3_ALGORITHM_SHA1 = 1, +} dnssec_nsec3_algorithm_t; + +/*! + * DNSSEC NSEC3 parameters. + */ +typedef struct dnssec_nsec3_params { + dnssec_nsec3_algorithm_t algorithm; /*!< NSEC3 algorithm. */ + uint8_t flags; /*!< NSEC3 flags. */ + uint16_t iterations; /*!< NSEC3 iterations count. */ + dnssec_binary_t salt; /*!< NSEC3 salt. */ +} dnssec_nsec3_params_t; + +/*! + * Free NSEC3 parameters. + */ +void dnssec_nsec3_params_free(dnssec_nsec3_params_t *params); + +/*! + * Parse NSEC3 parameters from NSEC3PARAM RDATA. + * + * \param params Output parameters. + * \param rdata NSEC3PARAM RDATA. + * + * \return Error code, DNSSEC_EOK if successful. + */ +int dnssec_nsec3_params_from_rdata(dnssec_nsec3_params_t *params, + const dnssec_binary_t *rdata); + +/*! + * Check whether a given NSEC bitmap contains a given RR type. + * + * \param bitmap Bitmap of an NSEC record. + * \param size Size of the bitmap. + * \param type RR type to check for. + * + * \return true if bitmap contains type, false otherwise. + */ +bool dnssec_nsec_bitmap_contains(const uint8_t *bitmap, uint16_t size, uint16_t type); + +/*! + * Compute NSEC3 hash for given data. + * + * \todo Input data must be converted to lowercase! + * + * \param[in] data Data to be hashed (usually domain name). + * \param[in] params NSEC3 parameters. + * \param[out] hash Computed hash (will be allocated or resized). + * + * \return Error code, DNSSEC_EOK if successful. + */ +int dnssec_nsec3_hash(const dnssec_binary_t *data, + const dnssec_nsec3_params_t *params, + dnssec_binary_t *hash); + +/*! + * Get length of raw NSEC3 hash for a given algorithm. + * + * \param algorithm NSEC3 algorithm number. + * + * \return Length of raw NSEC3 hash, zero on error. + */ +size_t dnssec_nsec3_hash_length(dnssec_nsec3_algorithm_t algorithm); + +struct dnssec_nsec_bitmap; + +/*! + * Context for encoding of RR types bitmap used in NSEC/NSEC3. + */ +typedef struct dnssec_nsec_bitmap dnssec_nsec_bitmap_t; + +/*! + * Allocate new bit map encoding context. + */ +dnssec_nsec_bitmap_t *dnssec_nsec_bitmap_new(void); + +/*! + * Clear existing bit map encoding context. + */ +void dnssec_nsec_bitmap_clear(dnssec_nsec_bitmap_t *bitmap); + +/*! + * Free bit map encoding context. + */ +void dnssec_nsec_bitmap_free(dnssec_nsec_bitmap_t *bitmap); + +/*! + * Add one RR type into the bitmap. + */ +void dnssec_nsec_bitmap_add(dnssec_nsec_bitmap_t *bitmap, uint16_t type); + +/*! + * Compute the size of the encoded bitmap. + */ +size_t dnssec_nsec_bitmap_size(const dnssec_nsec_bitmap_t *bitmap); + +/*! + * Write encoded bitmap into the given buffer. + */ +void dnssec_nsec_bitmap_write(const dnssec_nsec_bitmap_t *bitmap, uint8_t *output); + +/*! @} */ |