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 <utils/Errors.h>
18
19#ifndef CRYPTO_API_H_
20
21#define CRYPTO_API_H_
22
23namespace android {
24
25struct AString;
26struct CryptoPlugin;
27
28struct CryptoFactory {
29    CryptoFactory() {}
30    virtual ~CryptoFactory() {}
31
32    virtual bool isCryptoSchemeSupported(const uint8_t uuid[16]) const = 0;
33
34    virtual status_t createPlugin(
35            const uint8_t uuid[16], const void *data, size_t size,
36            CryptoPlugin **plugin) = 0;
37
38private:
39    CryptoFactory(const CryptoFactory &);
40    CryptoFactory &operator=(const CryptoFactory &);
41};
42
43struct CryptoPlugin {
44    enum Mode {
45        kMode_Unencrypted = 0,
46        kMode_AES_CTR     = 1,
47
48        // Neither key nor iv are being used in this mode.
49        // Each subsample is encrypted w/ an iv of all zeroes.
50        kMode_AES_WV      = 2,  // FIX constant
51    };
52
53    struct SubSample {
54        uint32_t mNumBytesOfClearData;
55        uint32_t mNumBytesOfEncryptedData;
56    };
57
58    CryptoPlugin() {}
59    virtual ~CryptoPlugin() {}
60
61    // If this method returns false, a non-secure decoder will be used to
62    // decode the data after decryption. The decrypt API below will have
63    // to support insecure decryption of the data (secure = false) for
64    // media data of the given mime type.
65    virtual bool requiresSecureDecoderComponent(const char *mime) const = 0;
66
67    // To implement resolution constraints, the crypto plugin needs to know
68    // the resolution of the video being decrypted.  The media player should
69    // call this method when the resolution is determined and any time it
70    // is subsequently changed.
71    virtual void notifyResolution(uint32_t width, uint32_t height) {}
72
73    // If the error returned falls into the range
74    // ERROR_DRM_VENDOR_MIN..ERROR_DRM_VENDOR_MAX, errorDetailMsg should be
75    // filled in with an appropriate string.
76    // At the java level these special errors will then trigger a
77    // MediaCodec.CryptoException that gives clients access to both
78    // the error code and the errorDetailMsg.
79    // Returns a non-negative result to indicate the number of bytes written
80    // to the dstPtr, or a negative result to indicate an error.
81    virtual ssize_t decrypt(
82            bool secure,
83            const uint8_t key[16],
84            const uint8_t iv[16],
85            Mode mode,
86            const void *srcPtr,
87            const SubSample *subSamples, size_t numSubSamples,
88            void *dstPtr,
89            AString *errorDetailMsg) = 0;
90
91private:
92    CryptoPlugin(const CryptoPlugin &);
93    CryptoPlugin &operator=(const CryptoPlugin &);
94};
95
96}  // namespace android
97
98extern "C" {
99    extern android::CryptoFactory *createCryptoFactory();
100}
101
102#endif  // CRYPTO_API_H_
103