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