1/*
2 * Copyright (C) 2012 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 <media/stagefright/MediaErrors.h>
18#include <utils/Errors.h>
19#include <utils/Vector.h>
20
21#ifndef CRYPTO_API_H_
22
23#define CRYPTO_API_H_
24
25namespace android {
26
27struct AString;
28struct CryptoPlugin;
29
30struct CryptoFactory {
31    CryptoFactory() {}
32    virtual ~CryptoFactory() {}
33
34    virtual bool isCryptoSchemeSupported(const uint8_t uuid[16]) const = 0;
35
36    virtual status_t createPlugin(
37            const uint8_t uuid[16], const void *data, size_t size,
38            CryptoPlugin **plugin) = 0;
39
40private:
41    CryptoFactory(const CryptoFactory &);
42    CryptoFactory &operator=(const CryptoFactory &);
43};
44
45struct CryptoPlugin {
46    enum Mode {
47        kMode_Unencrypted = 0,
48        kMode_AES_CTR     = 1,
49        kMode_AES_WV      = 2,
50        kMode_AES_CBC     = 3,
51    };
52
53    struct SubSample {
54        uint32_t mNumBytesOfClearData;
55        uint32_t mNumBytesOfEncryptedData;
56    };
57
58    struct Pattern {
59        // Number of blocks to be encrypted in the pattern. If zero, pattern
60        // encryption is inoperative.
61        uint32_t mEncryptBlocks;
62
63        // Number of blocks to be skipped (left clear) in the pattern. If zero,
64        // pattern encryption is inoperative.
65        uint32_t mSkipBlocks;
66    };
67
68    CryptoPlugin() {}
69    virtual ~CryptoPlugin() {}
70
71    // If this method returns false, a non-secure decoder will be used to
72    // decode the data after decryption. The decrypt API below will have
73    // to support insecure decryption of the data (secure = false) for
74    // media data of the given mime type.
75    virtual bool requiresSecureDecoderComponent(const char *mime) const = 0;
76
77    // To implement resolution constraints, the crypto plugin needs to know
78    // the resolution of the video being decrypted.  The media player should
79    // call this method when the resolution is determined and any time it
80    // is subsequently changed.
81
82    virtual void notifyResolution(uint32_t /* width */, uint32_t /* height */) {}
83
84    // A MediaDrm session may be associated with a MediaCrypto session.  The
85    // associated MediaDrm session is used to load decryption keys
86    // into the crypto/drm plugin.  The keys are then referenced by key-id
87    // in the 'key' parameter to the decrypt() method.
88    // Should return NO_ERROR on success, ERROR_DRM_SESSION_NOT_OPENED if
89    // the session is not opened and a code from MediaErrors.h otherwise.
90    virtual status_t setMediaDrmSession(const Vector<uint8_t> & /*sessionId */) {
91        return ERROR_UNSUPPORTED;
92    }
93
94    // If the error returned falls into the range
95    // ERROR_DRM_VENDOR_MIN..ERROR_DRM_VENDOR_MAX, errorDetailMsg should be
96    // filled in with an appropriate string.
97    // At the java level these special errors will then trigger a
98    // MediaCodec.CryptoException that gives clients access to both
99    // the error code and the errorDetailMsg.
100    // Returns a non-negative result to indicate the number of bytes written
101    // to the dstPtr, or a negative result to indicate an error.
102    virtual ssize_t decrypt(
103            bool secure,
104            const uint8_t key[16],
105            const uint8_t iv[16],
106            Mode mode,
107            const Pattern &pattern,
108            const void *srcPtr,
109            const SubSample *subSamples, size_t numSubSamples,
110            void *dstPtr,
111            AString *errorDetailMsg) = 0;
112
113private:
114    CryptoPlugin(const CryptoPlugin &);
115    CryptoPlugin &operator=(const CryptoPlugin &);
116};
117
118}  // namespace android
119
120extern "C" {
121    extern android::CryptoFactory *createCryptoFactory();
122}
123
124#endif  // CRYPTO_API_H_
125