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/*!
* \file edns.h
*
* \author Lubos Slovak <lubos.slovak@nic.cz>
*
* \brief Functions for manipulating and parsing EDNS OPT pseudo-RR.
*
* \addtogroup libknot
* @{
*/
/* 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/>.
*/
#ifndef _KNOT_EDNS_H_
#define _KNOT_EDNS_H_
#include <stdint.h>
#include "util/utils.h"
#include "rrset.h"
/*----------------------------------------------------------------------------*/
/*! \brief Structure representing one OPT RR Option. */
struct knot_opt_option {
uint16_t code;
uint16_t length;
uint8_t *data;
};
/*! \brief Structure representing one OPT RR Option. */
typedef struct knot_opt_option knot_opt_option_t;
/*!
* \brief Structure for holding EDNS parameters.
*
* \todo NSID
*/
struct knot_opt_rr {
uint16_t payload; /*!< UDP payload. */
uint8_t ext_rcode; /*!< Extended RCODE. */
/*!
* \brief Supported version of EDNS.
*
* Set to EDNS_NOT_SUPPORTED if not supported.
*/
uint8_t version;
uint16_t flags; /*!< EDNS flags. */
knot_opt_option_t *options; /*!< EDNS options. */
short option_count; /*!< Count of EDNS options in this OPT RR.*/
short options_max; /*!< Maximum count of options. */
short size; /*!< Total size of the OPT RR in wire format. */
};
/*! \brief Structure for holding EDNS parameters. */
typedef struct knot_opt_rr knot_opt_rr_t;
/*----------------------------------------------------------------------------*/
/*! \brief Constants for supported versions of EDNS. */
enum knot_edns_versions {
EDNS_VERSION_0 = (uint8_t)0, /*!< EDNS version 0. */
EDNS_NOT_SUPPORTED = (uint8_t)255 /*!< EDNS not supported. */
};
/*! \brief Constants for EDNS option codes. */
enum knot_edns_option_codes {
EDNS_OPTION_NSID = (uint16_t)3 /*!< NSID option code. */
};
/*! \brief Minimum size of EDNS OPT RR in wire format. */
static const short KNOT_EDNS_MIN_SIZE = 11;
/*----------------------------------------------------------------------------*/
/*!
* \brief Creates new empty OPT RR structure for holding EDNS parameters.
*
* \return New empty knot_opt_rr_t structure, or NULL if not successful.
*/
knot_opt_rr_t *knot_edns_new();
/*!
* \brief Initializes OPT RR structure from given OPT RR in wire format.
*
* \param opt_rr OPT RR structure to initialize.
* \param wire Wire format of the OPT RR to parse.
* \param max_size Maximum size of the wire format in bytes (may be more
* than acutal size of the OPT RR).
*
* \return Size of the parserd OPT RR in bytes if successful (always > 0).
* \retval KNOT_EINVAL
* \retval KNOT_EFEWDATA
* \retval KNOT_EMALF
* \retval KNOT_ENOMEM
*/
int knot_edns_new_from_wire(knot_opt_rr_t *opt_rr, const uint8_t *wire,
size_t max_size);
int knot_edns_new_from_rr(knot_opt_rr_t *opt_rr,
const knot_rrset_t *rrset);
/*!
* \brief Returns the UDP payload stored in the OPT RR.
*
* \warning This function does not check the parameter, so ensure to check it
* before calling the function. It must not be NULL.
* \note There is an assert() for debug checking of the parameter.
*
* \param opt_rr OPT RR structure to get the payload from.
*
* \return UDP payload in bytes.
*/
uint16_t knot_edns_get_payload(const knot_opt_rr_t *opt_rr);
/*!
* \brief Sets the UDP payload field in the OPT RR.
*
* \warning This function does not check the parameter, so ensure to check it
* before calling the function. It must not be NULL.
* \note There is an assert() for debug checking of the parameter.
*
* \param opt_rr OPT RR structure to set the payload to.
* \param payload UDP payload in bytes.
*/
void knot_edns_set_payload(knot_opt_rr_t *opt_rr, uint16_t payload);
/*!
* \brief Returns the Extended RCODE stored in the OPT RR.
*
* \warning This function does not check the parameter, so ensure to check it
* before calling the function. It must not be NULL.
* \note There is an assert() for debug checking of the parameter.
*
* \param opt_rr OPT RR structure to get the Extended RCODE from.
*
* \return Extended RCODE.
*/
uint8_t knot_edns_get_ext_rcode(const knot_opt_rr_t *opt_rr);
/*!
* \brief Sets the Extended RCODE field in the OPT RR.
*
* \warning This function does not check the parameter, so ensure to check it
* before calling the function. It must not be NULL.
* \note There is an assert() for debug checking of the parameter.
*
* \param opt_rr OPT RR structure to set the Extended RCODE to.
* \param ext_rcode Extended RCODE to set.
*/
void knot_edns_set_ext_rcode(knot_opt_rr_t *opt_rr, uint8_t ext_rcode);
/*!
* \brief Returns the EDNS version stored in the OPT RR.
*
* \warning This function does not check the parameter, so ensure to check it
* before calling the function. It must not be NULL.
* \note There is an assert() for debug checking of the parameter.
*
* \param opt_rr OPT RR structure to get the EDNS version from.
*
* \return EDNS version.
*/
uint8_t knot_edns_get_version(const knot_opt_rr_t *opt_rr);
/*!
* \brief Sets the EDNS version field in the OPT RR.
*
* \warning This function does not check the parameter, so ensure to check it
* before calling the function. It must not be NULL.
* \note There is an assert() for debug checking of the parameter.
*
* \param opt_rr OPT RR structure to set the EDNS version to.
* \param version EDNS version to set.
*/
void knot_edns_set_version(knot_opt_rr_t *opt_rr, uint8_t version);
/*!
* \brief Returns the flags stored in the OPT RR.
*
* \warning This function does not check the parameter, so ensure to check it
* before calling the function. It must not be NULL.
* \note There is an assert() for debug checking of the parameter.
*
* \param opt_rr OPT RR structure to get the flags from.
*
* \return EDNS flags.
*/
uint16_t knot_edns_get_flags(const knot_opt_rr_t *opt_rr);
/*!
* \brief Returns the state of the DO bit in the OPT RR flags.
*
* \param opt_rr OPT RR structure to get the DO bit from.
*
* \return <> 0 if the DO bit is set.
* \return 0 if the DO bit is not set.
*/
int knot_edns_do(const knot_opt_rr_t *opt_rr);
/*!
* \brief Sets the DO bit in the OPT RR.
*
* \param opt_rr OPT RR structure to set the DO bit in.
*/
void knot_edns_set_do(knot_opt_rr_t *opt_rr);
/*!
* \brief Adds EDNS Option to the OPT RR.
*
* \param opt_rr OPT RR structure to add the Option to.
* \param code Option code.
* \param length Option data length in bytes.
* \param data Option data.
*
* \retval KNOT_EOK
* \retval KNOT_ENOMEM
*/
int knot_edns_add_option(knot_opt_rr_t *opt_rr, uint16_t code,
uint16_t length, const uint8_t *data);
/*!
* \brief Checks if the OPT RR contains Option with the specified code.
*
* \param opt_rr OPT RR structure to check for the Option in.
* \param code Option code to check for.
*
* \retval <> 0 if the OPT RR contains Option with Option code \a code.
* \retval 0 otherwise.
*/
int knot_edns_has_option(const knot_opt_rr_t *opt_rr, uint16_t code);
/*!
* \brief Converts the given OPT RR into wire format.
*
* \param opt_rr OPT RR structure to convert into wire format.
* \param wire Place to put the wire format to.
* \param max_size Maximum space available for the wire format in bytes.
*
* \return Size of the wire format in bytes if successful.
* \retval KNOT_ESPACE
*/
short knot_edns_to_wire(const knot_opt_rr_t *opt_rr, uint8_t *wire,
size_t max_size);
/*!
* \brief Returns size of the OPT RR in wire format.
*
* \param opt_rr OPT RR to get the size of.
*
* \return Size of the OPT RR in bytes.
*/
short knot_edns_size(knot_opt_rr_t *opt_rr);
void knot_edns_free_options(knot_opt_rr_t *opt_rr);
/*!
* \brief Properly destroys the OPT RR structure.
*
* \note Also sets the given pointer to NULL.
*/
void knot_edns_free(knot_opt_rr_t **opt_rr);
#endif /* _KNOT_EDNS_H_ */
/*! @} */
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