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RIOT/sys/include/net/dns.h
2022-12-07 22:26:51 +01:00

105 lines
2.6 KiB
C

/*
* Copyright (C) 2019 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 DNS defines
* @ingroup net
* @brief Generic DNS values
* @{
*
* @file
* @brief Generic DNS values
*
* @author Martine Lenders <m.lenders@fu-berlin.de>
*/
#ifndef NET_DNS_H
#define NET_DNS_H
#include "modules.h"
#include "net/sock/dns.h"
#include "net/sock/dodtls.h"
#include "net/gcoap/dns.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
* @name DNS defines
* @{
*/
#define DNS_TYPE_A (1)
#define DNS_TYPE_AAAA (28)
#define DNS_CLASS_IN (1)
/** @} */
/**
* @name Field lengths
* @{
*/
#define RR_TYPE_LENGTH (2U)
#define RR_CLASS_LENGTH (2U)
#define RR_TTL_LENGTH (4U)
#define RR_RDLENGTH_LENGTH (2U)
/** @} */
/**
* @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
*/
static inline int dns_query(const char *domain_name, void *addr_out, int family)
{
int res = -ENOTSUP;
if (family == AF_UNSPEC) {
if (!IS_USED(MODULE_IPV4_ADDR)) {
family = AF_INET6;
}
else if (!IS_USED(MODULE_IPV6_ADDR)) {
family = AF_INET;
}
}
if (res <= 0 && IS_USED(MODULE_GCOAP_DNS)) {
res = gcoap_dns_query(domain_name, addr_out, family);
}
if (res <= 0 && IS_USED(MODULE_SOCK_DODTLS)) {
res = sock_dodtls_query(domain_name, addr_out, family);
}
if (res <= 0 && (IS_USED(MODULE_SOCK_DNS) || IS_USED(MODULE_SOCK_DNS_MOCK))) {
res = sock_dns_query(domain_name, addr_out, family);
}
return res;
}
#ifdef __cplusplus
}
#endif
#endif /* NET_DNS_H */
/** @} */