1 /*
2  * Copyright (C) 2020 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include "chpp/services/discovery.h"
18 
19 #include <stdbool.h>
20 #include <stddef.h>
21 #include <stdint.h>
22 
23 #include "chpp/app.h"
24 #include "chpp/common/discovery.h"
25 #include "chpp/log.h"
26 #include "chpp/macros.h"
27 #include "chpp/services.h"
28 #include "chpp/transport.h"
29 
30 /************************************************
31  *  Prototypes
32  ***********************************************/
33 
34 static void chppDiscoveryDiscoverAll(struct ChppAppState *context,
35                                      const struct ChppAppHeader *rxHeader);
36 
37 /************************************************
38  *  Private Functions
39  ***********************************************/
40 
41 /**
42  * Processes the Discover All Services (0x0001) request.
43  *
44  * @param context Maintains status for each app layer instance.
45  * @param requestHeader Request datagram header. Cannot be null.
46  */
47 static void chppDiscoveryDiscoverAll(
48     struct ChppAppState *context, const struct ChppAppHeader *requestHeader) {
49   // Allocate response
50   size_t responseLen =
51       sizeof(struct ChppAppHeader) +
52       context->registeredServiceCount * sizeof(struct ChppServiceDescriptor);
53 
54   struct ChppDiscoveryResponse *response = chppAllocServiceResponseTypedArray(
55       requestHeader, struct ChppDiscoveryResponse,
56       context->registeredServiceCount, services);
57 
58   if (response == NULL) {
59     CHPP_LOG_OOM();
60     CHPP_ASSERT(false);
61 
62   } else {
63     CHPP_LOGI("Discovery resp count=%" PRIu8, context->registeredServiceCount);
64 
65     response->header.error = CHPP_APP_ERROR_NONE;
66 
67     // Populate list of services
68     for (size_t i = 0; i < context->registeredServiceCount; i++) {
69       response->services[i] = context->registeredServices[i]->descriptor;
70     }
71 
72     // Send out response datagram
73     chppEnqueueTxDatagramOrFail(context->transportContext, response,
74                                 responseLen);
75   }
76 }
77 
78 /************************************************
79  *  Public Functions
80  ***********************************************/
81 
82 bool chppDispatchDiscoveryClientRequest(struct ChppAppState *context,
83                                         const uint8_t *buf, size_t len) {
84   UNUSED_VAR(len);
85   const struct ChppAppHeader *rxHeader = (const struct ChppAppHeader *)buf;
86   bool success = true;
87 
88   switch (rxHeader->command) {
89     case CHPP_DISCOVERY_COMMAND_DISCOVER_ALL: {
90       // Send back a list of services supported by this platform.
91       chppDiscoveryDiscoverAll(context, rxHeader);
92       break;
93     }
94     default: {
95       success = false;
96     }
97   }
98   return success;
99 }
100