mirror of
https://github.com/RIOT-OS/RIOT.git
synced 2024-12-29 04:50:03 +01:00
122 lines
3.7 KiB
C
122 lines
3.7 KiB
C
/*
|
|
* Copyright (C) 2021 Freie Universität Berlin
|
|
*
|
|
* This file is subject to the terms and conditions of the GNU Lesser
|
|
* General Public License v2.1. See the file LICENSE in the top level
|
|
* directory for more details.
|
|
*/
|
|
|
|
/**
|
|
* @defgroup net_dns_msg DNS message parser and composer
|
|
* @ingroup net_dns
|
|
* @brief Parsing and composition of DNS messages
|
|
* @{
|
|
*
|
|
* @file
|
|
* @brief Definitions for parsing and composition of DNS messages
|
|
*
|
|
* @author Martine Lenders <m.lenders@fu-berlin.de>
|
|
*/
|
|
#ifndef NET_DNS_MSG_H
|
|
#define NET_DNS_MSG_H
|
|
|
|
#include <stdint.h>
|
|
#include <stdlib.h>
|
|
|
|
#ifdef __cplusplus
|
|
extern "C" {
|
|
#endif
|
|
|
|
/**
|
|
* @defgroup net_dns_msg_conf DNS message parsing and composition configuration
|
|
* @ingroup config
|
|
* @{
|
|
*/
|
|
/**
|
|
* @brief maximum DNS message length
|
|
*/
|
|
#ifndef CONFIG_DNS_MSG_LEN
|
|
#define CONFIG_DNS_MSG_LEN (128U)
|
|
#endif /* CONFIG_DNS_MSG_LEN */
|
|
/** @} */
|
|
|
|
/**
|
|
* @brief DNS internal structure
|
|
*
|
|
* @see [RFC 1035, section 4.1.1](https://tools.ietf.org/html/rfc1035#section-4.1.1)
|
|
*/
|
|
typedef struct __attribute__((packed)) {
|
|
uint16_t id; /**< identifier */
|
|
/**
|
|
* @brief flags
|
|
*
|
|
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
|
* |QR| Opcode |AA|TC|RD|RA|Z |AD|CD| RCODE |
|
|
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|
|
*
|
|
* - QR: Query (0) or Response (1)
|
|
* - Opcode: Kind of query
|
|
* - AA: Authoritative Answer
|
|
* - TC: Truncated
|
|
* - RD: Recursion Desired
|
|
* - RA: Recursion Available
|
|
* - Z: Reserved
|
|
* - AD: Authentic Data (see [RFC 4035](https://tools.ietf.org/html/4035))
|
|
* - CD: Checking Disabled (see [RFC 4035](https://tools.ietf.org/html/4035))
|
|
* - RCODE: Response Code
|
|
*/
|
|
uint16_t flags;
|
|
uint16_t qdcount; /**< number of question entries */
|
|
uint16_t ancount; /**< number of answer resource records */
|
|
uint16_t nscount; /**< number of name server resource records */
|
|
uint16_t arcount; /**< number of additional records */
|
|
uint8_t payload[]; /**< payload */
|
|
} dns_hdr_t;
|
|
|
|
/**
|
|
* @brief Composes a DNS query message
|
|
*
|
|
* The query will request an A or AAAA IN record for @p domain_name depending on
|
|
* @p family:
|
|
*
|
|
* - When @p family is `AF_INET` or `AF_UNSPEC` a query for an A record will be
|
|
* added
|
|
* - When @p family is `AF_INET6` or `AF_UNSPEC` a query for an AAAA record will
|
|
* be added
|
|
*
|
|
* @param[out] dns_buf A buffer of length @ref CONFIG_DNS_MSG_LEN
|
|
* @param[in] domain_name The domain name to query.
|
|
* @param[in] id The ID for the query.
|
|
* @param[in] family Either `AF_UNSPEC`, `AF_INET`, or `AF_INET6`.
|
|
* Determines the address records for @p domain_name
|
|
* queried.
|
|
*
|
|
* @return Size of the composed query in bytes.
|
|
*/
|
|
size_t dns_msg_compose_query(void *dns_buf, const char *domain_name,
|
|
uint16_t id, int family);
|
|
|
|
/**
|
|
* @brief Parses a DNS response message
|
|
*
|
|
* @param[in] buf The message to parse.
|
|
* @param[in] len Length of @p buf.
|
|
* @param[in] family The address family used to compose the query for
|
|
* this response (see @ref dns_msg_compose_query())
|
|
* @param[out] addr_out The IP address returned by the response.
|
|
* @param[out] ttl The live time of the entry in seconds
|
|
*
|
|
* @return Length of the @p addr_out on success.
|
|
* @return -EBADMSG, when an address corresponding to @p family can not be found
|
|
* in @p buf.
|
|
*/
|
|
int dns_msg_parse_reply(const uint8_t *buf, size_t len, int family,
|
|
void *addr_out, uint32_t *ttl);
|
|
|
|
#ifdef __cplusplus
|
|
}
|
|
#endif
|
|
|
|
#endif /* NET_DNS_MSG_H */
|
|
/** @} */
|