1 /*
2  * Copyright 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 #pragma once
18 
19 #include "gatekeeper/gatekeeper_messages.h"
20 
21 #include "common/libs/fs/shared_fd.h"
22 
23 #include <memory>
24 
25 namespace gatekeeper {
26 
27 /**
28  * GatekeeperRawMessage - Header and raw byte payload for a serialized
29  * gatekeeper message.
30  *
31  * @cmd: the command, one of gatekeeper::ENROLL and gatekeeper::VERIFY.
32  * @payload: start of the serialized command specific payload
33  */
34 struct GatekeeperRawMessage {
35     uint32_t cmd : 31;
36     bool is_response : 1;
37     uint32_t payload_size;
38     uint8_t payload[0];
39 };
40 
41 } // namespace gatekeeper
42 
43 namespace cuttlefish {
44 
45 using gatekeeper::GatekeeperRawMessage;
46 
47 /**
48  * A destroyer for GatekeeperRawMessage instances created with
49  * CreateGatekeeperMessage. Wipes memory from the GatekeeperRawMessage instances.
50  */
51 class GatekeeperCommandDestroyer {
52 public:
53   void operator()(GatekeeperRawMessage* ptr);
54 };
55 
56 /** An owning pointer for a GatekeeperRawMessage instance. */
57 using ManagedGatekeeperMessage =
58     std::unique_ptr<GatekeeperRawMessage, GatekeeperCommandDestroyer>;
59 
60 /**
61  * Allocates memory for a GatekeeperRawMessage carrying a message of size
62  * `payload_size`.
63  */
64 ManagedGatekeeperMessage CreateGatekeeperMessage(
65     uint32_t command, bool is_response, size_t payload_size);
66 
67 /*
68  * Interface for communication channels that synchronously communicate Gatekeeper
69  * IPC/RPC calls. Sends messages over a file descriptor.
70  */
71 class GatekeeperChannel {
72 public:
73   GatekeeperChannel(SharedFD channel);
74 
75   bool SendRequest(uint32_t command,
76                    const gatekeeper::GateKeeperMessage& message);
77   bool SendResponse(uint32_t command,
78                     const gatekeeper::GateKeeperMessage& message);
79   ManagedGatekeeperMessage ReceiveMessage();
80 private:
81   SharedFD channel_;
82   bool SendMessage(uint32_t command, bool response,
83                    const gatekeeper::GateKeeperMessage& message);
84 };
85 
86 } // namespace cuttlefish
87