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/* Copyright (C) 2019 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 <https://www.gnu.org/licenses/>.
*/
/*!
* \file
*
* \brief API for manipulating rdata.
*
* \addtogroup rr
* @{
*/
#pragma once
#include <assert.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>
/*!< \brief Maximum rdata length. */
#define KNOT_RDATA_MAXLEN 65535
/*!
* \brief Structure holding single rdata payload.
*/
typedef struct {
uint16_t len;
uint8_t data[];
} knot_rdata_t;
/*!
* \brief Inits rdata structure.
*
* \param rdata Rdata structure to be initialized. At least knot_rdata_size bytes
* must fit into it!
* \param len Rdata length.
* \param data Rdata itself.
*/
inline static void knot_rdata_init(knot_rdata_t *rdata, uint16_t len, const uint8_t *data)
{
assert(rdata);
rdata->len = len;
if (rdata->len > 0) {
assert(data);
memcpy(rdata->data, data, len);
if (len & 1) { // Initialize possible padding to mute analytical tools.
rdata->data[len] = 0;
}
}
}
/*!
* \brief Returns actual size of the rdata structure for given rdata length.
*
* \param len Rdata length.
*
* \return Actual structure size.
*/
inline static size_t knot_rdata_size(uint16_t len)
{
return sizeof(uint16_t) + len + (len & 1);
}
/*!
* \brief Canonical comparison of two rdata structures.
*
* \param rdata1 First rdata to compare.
* \param rdata2 Second rdata to compare.
*
* \retval = 0 if rdata1 == rdata2.
* \retval < 0 if rdata1 < rdata2.
* \retval > 0 if rdata1 > rdata2.
*/
inline static int knot_rdata_cmp(const knot_rdata_t *rdata1, const knot_rdata_t *rdata2)
{
assert(rdata1);
assert(rdata2);
size_t common_len = (rdata1->len <= rdata2->len) ? rdata1->len : rdata2->len;
int cmp = memcmp(rdata1->data, rdata2->data, common_len);
if (cmp == 0 && rdata1->len != rdata2->len) {
cmp = rdata1->len < rdata2->len ? -1 : 1;
}
return cmp;
}
/*! @} */
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