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/* Copyright (C) 2011 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 nsec-bitmap.h
*
* \author Jan Vcelak <jan.vcelak@nic.cz>
*
* \brief RR bitmap used in NSEC/NSEC3 records (RFC 4034).
*
* \addtogroup dnssec
* @{
*/
#ifndef _KNOT_DNSSEC_ZONE_NSEC_BITMAP_H_
#define _KNOT_DNSSEC_ZONE_NSEC_BITMAP_H_
#include <stdint.h>
#include <string.h>
#include "libknot/zone/node.h"
#include "libknot/rrset.h"
#include "common/descriptor.h"
#define BITMAP_WINDOW_SIZE 256
#define BITMAP_WINDOW_BYTES (BITMAP_WINDOW_SIZE/CHAR_BIT)
#define BITMAP_WINDOW_COUNT 256
/*!
* \brief One window of a bitmap.
*/
typedef struct {
uint8_t used;
uint8_t data[BITMAP_WINDOW_BYTES];
} bitmap_window_t;
/*!
* \brief Bitmap of RR types.
*/
typedef struct {
int used;
bitmap_window_t windows[BITMAP_WINDOW_COUNT];
} bitmap_t;
/*!
* \brief Add one RR type into the bitmap.
*/
inline static void bitmap_add_type(bitmap_t *bitmap, uint16_t type)
{
int win = type / BITMAP_WINDOW_SIZE;
int bit = type % BITMAP_WINDOW_SIZE;
if (bitmap->used <= win) {
bitmap->used = win + 1;
}
int win_byte = bit / CHAR_BIT;
int win_bit = bit % CHAR_BIT;
bitmap_window_t *window = &bitmap->windows[win];
window->data[win_byte] |= 0x80 >> win_bit;
if (window->used <= win_byte) {
window->used = win_byte + 1;
}
}
/*!
* \brief Add all RR types from a node into the bitmap.
*/
inline static void bitmap_add_node_rrsets(bitmap_t *bitmap,
const knot_node_t *node)
{
const knot_rrset_t **node_rrsets = knot_node_rrsets_no_copy(node);
for (int i = 0; i < node->rrset_count; i++) {
const knot_rrset_t *rr = node_rrsets[i];
if (rr->type != KNOT_RRTYPE_NSEC && rr->rdata_count > 0) {
bitmap_add_type(bitmap, node_rrsets[i]->type);
}
}
}
/*!
* \brief Compute the size of the bitmap in NSEC RDATA format.
*/
inline static size_t bitmap_size(const bitmap_t *bitmap)
{
size_t result = 0;
for (int i = 0; i < bitmap->used; i++) {
int used = bitmap->windows[i].used;
if (used == 0) {
continue;
}
result += 2 + used; // windows number, window size, data
}
return result;
}
/*!
* \brief Write bitmap in NSEC RDATA format.
*/
inline static void bitmap_write(const bitmap_t *bitmap, uint8_t *output)
{
uint8_t *write_ptr = output;
for (int win = 0; win < bitmap->used; win++) {
int used = bitmap->windows[win].used;
if (used == 0) {
continue;
}
*write_ptr = (uint8_t)win;
write_ptr += 1;
*write_ptr = (uint8_t)used;
write_ptr += 1;
memcpy(write_ptr, bitmap->windows[win].data, used);
write_ptr += used;
}
}
#endif // _KNOT_DNSSEC_ZONE_NSEC_BITMAP_H_
/*! @} */
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