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RIOT/sys/include/net/sock/dns.h

119 lines
3.0 KiB
C

/*
* Copyright (C) 2017 Kaspar Schleiser <kaspar@schleiser.de>
*
* 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_sock_dns DNS sock API
* @ingroup net_sock
*
* @brief Sock DNS client
*
* @{
*
* @file
* @brief DNS sock definitions
*
* @author Kaspar Schleiser <kaspar@schleiser.de>
* @author Hendrik van Essen <hendrik.ve@fu-berlin.de>
*/
#ifndef NET_SOCK_DNS_H
#define NET_SOCK_DNS_H
#include <errno.h>
#include <stdint.h>
#include <unistd.h>
#include "net/dns/msg.h"
#include "net/sock/udp.h"
#ifdef __cplusplus
extern "C" {
#endif
#ifdef MODULE_AUTO_INIT_SOCK_DNS
/**
* @brief IP version of the address provided with CONFIG_AUTO_INIT_SOCK_DNS_SERVER_ADDR
*/
#ifndef CONFIG_AUTO_INIT_SOCK_DNS_IP_VERSION
/* IPv6 is preferred */
#if defined(SOCK_HAS_IPV6)
#define CONFIG_AUTO_INIT_SOCK_DNS_IP_VERSION 6
#elif defined(SOCK_HAS_IPV4)
#define CONFIG_AUTO_INIT_SOCK_DNS_IP_VERSION 4
#else
#error "Neither IPv4 nor IPv6 included in build"
#endif
#endif
/**
* @brief Address of the DNS server
*/
#ifndef CONFIG_AUTO_INIT_SOCK_DNS_SERVER_ADDR
/* Default to Google Public DNS */
#if CONFIG_AUTO_INIT_SOCK_DNS_IP_VERSION == 6
#define CONFIG_AUTO_INIT_SOCK_DNS_SERVER_ADDR "2001:4860:4860::8888"
#elif CONFIG_AUTO_INIT_SOCK_DNS_IP_VERSION == 4
#define CONFIG_AUTO_INIT_SOCK_DNS_SERVER_ADDR "8.8.8.8"
#endif
#endif
/**
* @brief Port of the DNS server
*/
#ifndef CONFIG_AUTO_INIT_SOCK_DNS_SERVER_PORT
#define CONFIG_AUTO_INIT_SOCK_DNS_SERVER_PORT SOCK_DNS_PORT
#endif
#endif /* MODULE_AUTO_INIT_SOCK_DNS */
/**
* @name DNS defines
* @{
*/
#define SOCK_DNS_PORT (53)
#define SOCK_DNS_RETRIES (2)
#define SOCK_DNS_MAX_NAME_LEN (CONFIG_DNS_MSG_LEN - sizeof(dns_hdr_t) - 4)
/** @} */
/**
* @brief Get IP address for DNS name
*
* This function will synchronously try to resolve a DNS A or AAAA record by contacting
* the DNS server specified in the global variable @ref sock_dns_server.
*
* By supplying AF_INET, AF_INET6 or AF_UNSPEC in @p family requesting of A
* records (IPv4), AAAA records (IPv6) or both can be selected.
*
* This function will return the first DNS record it receives. IF both A and
* AAAA are requested, AAAA will be preferred.
*
* @note @p addr_out needs to provide space for any possible result!
* (4byte when family==AF_INET, 16byte otherwise)
*
* @param[in] domain_name DNS name to resolve into address
* @param[out] addr_out buffer to write result into
* @param[in] family Either AF_INET, AF_INET6 or AF_UNSPEC
*
* @return the size of the resolved address on success
* @return < 0 otherwise
*/
int sock_dns_query(const char *domain_name, void *addr_out, int family);
/**
* @brief global DNS server endpoint
*/
extern sock_udp_ep_t sock_dns_server;
#ifdef __cplusplus
}
#endif
#endif /* NET_SOCK_DNS_H */
/** @} */