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/* 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 "libdnssec/nsec.h"
#include "libdnssec/shared/shared.h"
#include "libdnssec/shared/binary_wire.h"
#include "libdnssec/binary.h"
#include "libdnssec/error.h"
/*!
* Free NSEC3 parameters.
*/
_public_
void dnssec_nsec3_params_free(dnssec_nsec3_params_t *params)
{
if (!params) {
return;
}
dnssec_binary_free(¶ms->salt);
clear_struct(params);
}
/*!
* Parse NSEC3 parameters from NSEC3PARAM RDATA.
*
* \see RFC 5155 (section 4.2)
*/
_public_
int dnssec_nsec3_params_from_rdata(dnssec_nsec3_params_t *params,
const dnssec_binary_t *rdata)
{
if (!params || !rdata || !rdata->data) {
return DNSSEC_EINVAL;
}
dnssec_nsec3_params_t new_params = { 0 };
wire_ctx_t wire = binary_init(rdata);
if (wire_ctx_available(&wire) < 5) {
return DNSSEC_MALFORMED_DATA;
}
new_params.algorithm = wire_ctx_read_u8(&wire);
new_params.flags = wire_ctx_read_u8(&wire);
new_params.iterations = wire_ctx_read_u16(&wire);
new_params.salt.size = wire_ctx_read_u8(&wire);
if (wire_ctx_available(&wire) != new_params.salt.size) {
return DNSSEC_MALFORMED_DATA;
}
new_params.salt.data = malloc(new_params.salt.size);
if (new_params.salt.data == NULL) {
return DNSSEC_ENOMEM;
}
binary_read(&wire, &new_params.salt);
assert(wire_ctx_offset(&wire) == rdata->size);
*params = new_params;
return DNSSEC_EOK;
}
_public_
bool dnssec_nsec_bitmap_contains(const uint8_t *bitmap, uint16_t size, uint16_t type)
{
if (!bitmap || size == 0) {
return false;
}
const uint8_t type_hi = (type >> 8); // Which window block contains type.
const uint8_t type_lo = (type & 0xff);
const uint8_t bitmap_idx = (type_lo >> 3); // Which byte in the window block contains type.
const uint8_t bit_mask = 1 << (7 - (type_lo & 0x07)); // Which bit in the byte represents type.
size_t bitmap_pos = 0;
while (bitmap_pos + 3 <= size) {
uint8_t block_idx = bitmap[bitmap_pos++]; // Skip window block No.
uint8_t block_size = bitmap[bitmap_pos++]; // Skip window block size.
// Size checks.
if (block_size == 0 || bitmap_pos + block_size > size) {
return false;
}
// Check whether we found the correct window block.
if (block_idx == type_hi) {
if (bitmap_idx < block_size) {
// Check if the bit for type is set.
return bitmap[bitmap_pos + bitmap_idx] & bit_mask;
}
return false;
} else {
bitmap_pos += block_size;
}
}
return false;
}
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