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1 /*
2  * Copyright (C) 2017 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 #ifndef CLEARKEY_SESSION_LIBRARY_H_
18 #define CLEARKEY_SESSION_LIBRARY_H_
19 
20 #include <media/cas/CasAPI.h>
21 #include <media/cas/DescramblerAPI.h>
22 #include <openssl/aes.h>
23 #include <utils/KeyedVector.h>
24 #include <utils/Mutex.h>
25 #include <utils/RefBase.h>
26 
27 namespace android {
28 struct ABuffer;
29 
30 namespace clearkeycas {
31 class KeyFetcher;
32 
33 class ClearKeyCasSession : public RefBase {
34 public:
35     explicit ClearKeyCasSession(CasPlugin *plugin);
36 
37     virtual ~ClearKeyCasSession();
38 
39     ssize_t decrypt(
40             bool secure,
41             DescramblerPlugin::ScramblingControl scramblingControl,
42             size_t numSubSamples,
43             const DescramblerPlugin::SubSample *subSamples,
44             const void *srcPtr,
45             void *dstPtr,
46             AString * /* errorDetailMsg */);
47 
48     status_t updateECM(KeyFetcher *keyFetcher, void *ecm, size_t size);
49 
50 private:
51     enum {
52         kNumKeys = 2,
53     };
54     struct KeyInfo {
55         bool valid;
56         AES_KEY contentKey;
57     };
58     sp<ABuffer> mEcmBuffer;
59     Mutex mKeyLock;
60     CasPlugin* mPlugin;
61     KeyInfo mKeyInfo[kNumKeys];
62 
63     friend class ClearKeySessionLibrary;
64 
getPlugin()65     CasPlugin* getPlugin() const { return mPlugin; }
66     status_t decryptPayload(
67             const AES_KEY& key, size_t length, size_t offset, char* buffer) const;
68 
69     DISALLOW_EVIL_CONSTRUCTORS(ClearKeyCasSession);
70 };
71 
72 class ClearKeySessionLibrary {
73 public:
74     static ClearKeySessionLibrary* get();
75 
76     status_t addSession(CasPlugin *plugin, CasSessionId *sessionId);
77 
78     std::shared_ptr<ClearKeyCasSession> findSession(const CasSessionId& sessionId);
79 
80     void destroySession(const CasSessionId& sessionId);
81 
82     void destroyPlugin(CasPlugin *plugin);
83 
84 private:
85     static Mutex sSingletonLock;
86     static ClearKeySessionLibrary* sSingleton;
87 
88     Mutex mSessionsLock;
89     uint32_t mNextSessionId;
90     KeyedVector<CasSessionId, std::shared_ptr<ClearKeyCasSession>> mIDToSessionMap;
91 
92     ClearKeySessionLibrary();
93     DISALLOW_EVIL_CONSTRUCTORS(ClearKeySessionLibrary);
94 };
95 
96 } // namespace clearkeycas
97 } // namespace android
98 
99 #endif // CLEARKEY_SESSION_LIBRARY_H_
100