mbed-os/features/netsocket/DNS.h

98 lines
4.2 KiB
C++

/*
* Copyright (c) 2018 ARM Limited
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef DNS_H
#define DNS_H
class DNS {
public:
/** Translates a hostname to an IP address with specific version
*
* The hostname may be either a domain name or an IP address. If the
* hostname is an IP address, no network transactions will be performed.
*
* If no stack-specific DNS resolution is provided, the hostname
* will be resolve using a UDP socket on the stack.
*
* @param host Hostname to resolve
* @param address Destination for the host SocketAddress
* @param version IP version of address to resolve, NSAPI_UNSPEC indicates
* version is chosen by the stack (defaults to NSAPI_UNSPEC)
* @return 0 on success, negative error code on failure
*/
virtual nsapi_error_t gethostbyname(const char *host,
SocketAddress *address, nsapi_version_t version = NSAPI_UNSPEC) = 0;
/** Hostname translation callback (asynchronous)
*
* Callback will be called after DNS resolution completes or a failure occurs.
*
* Callback should not take more than 10ms to execute, otherwise it might
* prevent underlying thread processing. A portable user of the callback
* should not make calls to network operations due to stack size limitations.
* The callback should not perform expensive operations such as socket recv/send
* calls or blocking operations.
*
* @param status 0 on success, negative error code on failure
* @param address On success, destination for the host SocketAddress
*/
typedef mbed::Callback<void (nsapi_error_t result, SocketAddress *address)> hostbyname_cb_t;
/** Translates a hostname to an IP address (asynchronous)
*
* The hostname may be either a domain name or an IP address. If the
* hostname is an IP address, no network transactions will be performed.
*
* If no stack-specific DNS resolution is provided, the hostname
* will be resolve using a UDP socket on the stack.
*
* Call is non-blocking. Result of the DNS operation is returned by the callback.
* If this function returns failure, callback will not be called. In case result
* is success (IP address was found from DNS cache), callback will be called
* before function returns.
*
* @param host Hostname to resolve
* @param callback Callback that is called for result
* @param version IP version of address to resolve, NSAPI_UNSPEC indicates
* version is chosen by the stack (defaults to NSAPI_UNSPEC)
* @return 0 on immediate success,
* negative error code on immediate failure or
* a positive unique id that represents the hostname translation operation
* and can be passed to cancel
*/
virtual nsapi_value_or_error_t gethostbyname_async(const char *host, hostbyname_cb_t callback,
nsapi_version_t version = NSAPI_UNSPEC) = 0;
/** Cancels asynchronous hostname translation
*
* When translation is cancelled, callback will not be called.
*
* @param id Unique id of the hostname translation operation
* @return 0 on success, negative error code on failure
*/
virtual nsapi_error_t gethostbyname_async_cancel(int id) = 0;
/** Add a domain name server to list of servers to query
*
* @param address Destination for the host address
* @return 0 on success, negative error code on failure
*/
virtual nsapi_error_t add_dns_server(const SocketAddress &address) = 0;
};
#endif