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Diff: mbed-os/features/netsocket/DNS.h
- Revision:
- 0:8fdf9a60065b
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed-os/features/netsocket/DNS.h Wed Oct 10 00:33:53 2018 +0000 @@ -0,0 +1,97 @@ +/* + * 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