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 DESCRAMBLER_API_H_ 18 #define DESCRAMBLER_API_H_ 19 20 #include <media/stagefright/MediaErrors.h> 21 #include <media/cas/CasAPI.h> 22 23 namespace android { 24 25 struct AString; 26 struct DescramblerPlugin; 27 28 struct DescramblerFactory { DescramblerFactoryDescramblerFactory29 DescramblerFactory() {} ~DescramblerFactoryDescramblerFactory30 virtual ~DescramblerFactory() {} 31 32 // Determine if the plugin can handle the CA scheme identified by CA_system_id. 33 virtual bool isSystemIdSupported( 34 int32_t CA_system_id) const = 0; 35 36 // Construct a new instance of a DescramblerPlugin given a CA_system_id 37 virtual status_t createPlugin( 38 int32_t CA_system_id, DescramblerPlugin **plugin) = 0; 39 40 private: 41 DescramblerFactory(const DescramblerFactory &); 42 DescramblerFactory &operator=(const DescramblerFactory &); 43 }; 44 45 struct DescramblerPlugin { 46 enum ScramblingControl { 47 kScrambling_Unscrambled = 0, 48 kScrambling_Reserved = 1, 49 kScrambling_EvenKey = 2, 50 kScrambling_OddKey = 3, 51 }; 52 53 struct SubSample { 54 uint32_t mNumBytesOfClearData; 55 uint32_t mNumBytesOfEncryptedData; 56 }; 57 DescramblerPluginDescramblerPlugin58 DescramblerPlugin() {} ~DescramblerPluginDescramblerPlugin59 virtual ~DescramblerPlugin() {} 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 // A MediaCas session may be associated with a MediaCrypto session. The 68 // associated MediaCas session is used to load decryption keys 69 // into the crypto/cas plugin. The keys are then referenced by key-id 70 // in the 'key' parameter to the decrypt() method. 71 // Should return NO_ERROR on success, ERROR_DRM_SESSION_NOT_OPENED if 72 // the session is not opened and a code from MediaErrors.h otherwise. 73 virtual status_t setMediaCasSession(const CasSessionId& sessionId) = 0; 74 75 // If the error returned falls into the range 76 // ERROR_DRM_VENDOR_MIN..ERROR_DRM_VENDOR_MAX, errorDetailMsg should be 77 // filled in with an appropriate string. 78 // At the java level these special errors will then trigger a 79 // MediaCodec.CryptoException that gives clients access to both 80 // the error code and the errorDetailMsg. 81 // Returns a non-negative result to indicate the number of bytes written 82 // to the dstPtr, or a negative result to indicate an error. 83 virtual ssize_t descramble( 84 bool secure, 85 ScramblingControl scramblingControl, 86 size_t numSubSamples, 87 const SubSample *subSamples, 88 const void *srcPtr, 89 int32_t srcOffset, 90 void *dstPtr, 91 int32_t dstOffset, 92 AString *errorDetailMsg) = 0; 93 94 private: 95 DescramblerPlugin(const DescramblerPlugin &); 96 DescramblerPlugin &operator=(const DescramblerPlugin &); 97 }; 98 99 } // namespace android 100 101 extern "C" { 102 extern android::DescramblerFactory *createDescramblerFactory(); 103 } 104 105 #endif // DESCRAMBLER_API_H_ 106