1 /*
2  *  Copyright (c) 2023, The OpenThread Authors.
3  *  All rights reserved.
4  *
5  *  Redistribution and use in source and binary forms, with or without
6  *  modification, are permitted provided that the following conditions are met:
7  *  1. Redistributions of source code must retain the above copyright
8  *     notice, this list of conditions and the following disclaimer.
9  *  2. Redistributions in binary form must reproduce the above copyright
10  *     notice, this list of conditions and the following disclaimer in the
11  *     documentation and/or other materials provided with the distribution.
12  *  3. Neither the name of the copyright holder nor the
13  *     names of its contributors may be used to endorse or promote products
14  *     derived from this software without specific prior written permission.
15  *
16  *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17  *  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  *  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
20  *  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23  *  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24  *  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25  *  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26  *  POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 /**
30  * @file
31  * @brief
32  *   This file defines the platform DNS interface.
33  *
34  */
35 
36 #ifndef OPENTHREAD_PLATFORM_DNS_H_
37 #define OPENTHREAD_PLATFORM_DNS_H_
38 
39 #include <openthread/instance.h>
40 #include <openthread/message.h>
41 
42 #ifdef __cplusplus
43 extern "C" {
44 #endif
45 
46 /**
47  * @addtogroup plat-dns
48  *
49  * @brief
50  *   This module includes the platform abstraction for sending recursive DNS query to upstream DNS servers.
51  *
52  * @{
53  *
54  */
55 
56 /**
57  * This opaque type represents an upstream DNS query transaction.
58  *
59  */
60 typedef struct otPlatDnsUpstreamQuery otPlatDnsUpstreamQuery;
61 
62 /**
63  * Starts an upstream query transaction.
64  *
65  * - In success case (and errors represented by DNS protocol messages), the platform is expected to call
66  *   `otPlatDnsUpstreamQueryDone`.
67  * - The OpenThread core may cancel a (possibly timeout) query transaction by calling
68  *   `otPlatDnsCancelUpstreamQuery`, the platform must not call `otPlatDnsUpstreamQueryDone` on a
69  *   cancelled transaction.
70  *
71  * @param[in] aInstance  The OpenThread instance structure.
72  * @param[in] aTxn       A pointer to the opaque DNS query transaction object.
73  * @param[in] aQuery     A message buffer of the DNS payload that should be sent to upstream DNS server.
74  *
75  */
76 void otPlatDnsStartUpstreamQuery(otInstance *aInstance, otPlatDnsUpstreamQuery *aTxn, const otMessage *aQuery);
77 
78 /**
79  * Cancels a transaction of upstream query.
80  *
81  * The platform must call `otPlatDnsUpstreamQueryDone` to release the resources.
82  *
83  * @param[in] aInstance  The OpenThread instance structure.
84  * @param[in] aTxn       A pointer to the opaque DNS query transaction object.
85  *
86  */
87 void otPlatDnsCancelUpstreamQuery(otInstance *aInstance, otPlatDnsUpstreamQuery *aTxn);
88 
89 /**
90  * The platform calls this function to finish DNS query.
91  *
92  * The transaction will be released, so the platform must not call on the same transaction twice. This function passes
93  * the ownership of `aResponse` to OpenThread stack.
94  *
95  * Platform can pass a nullptr to close a transaction without a response.
96  *
97  * @param[in] aInstance  The OpenThread instance structure.
98  * @param[in] aTxn       A pointer to the opaque DNS query transaction object.
99  * @param[in] aResponse  A message buffer of the DNS response payload or `nullptr` to close a transaction without a
100  *                       response.
101  *
102  */
103 extern void otPlatDnsUpstreamQueryDone(otInstance *aInstance, otPlatDnsUpstreamQuery *aTxn, otMessage *aResponse);
104 
105 /**
106  * @}
107  *
108  */
109 
110 #ifdef __cplusplus
111 }
112 #endif
113 
114 #endif
115