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 kScrambling_Mask_Key = 0x3, 52 53 // Hint that the descrambling request is for a PES header only 54 kScrambling_Flag_PesHeader = (1 << 31), 55 }; 56 57 struct SubSample { 58 uint32_t mNumBytesOfClearData; 59 uint32_t mNumBytesOfEncryptedData; 60 }; 61 DescramblerPluginDescramblerPlugin62 DescramblerPlugin() {} ~DescramblerPluginDescramblerPlugin63 virtual ~DescramblerPlugin() {} 64 65 // If this method returns false, a non-secure decoder will be used to 66 // decode the data after decryption. The decrypt API below will have 67 // to support insecure decryption of the data (secure = false) for 68 // media data of the given mime type. 69 virtual bool requiresSecureDecoderComponent(const char *mime) const = 0; 70 71 // A MediaCas session may be associated with a MediaCrypto session. The 72 // associated MediaCas session is used to load decryption keys 73 // into the crypto/cas plugin. The keys are then referenced by key-id 74 // in the 'key' parameter to the decrypt() method. 75 // Should return NO_ERROR on success, ERROR_CAS_SESSION_NOT_OPENED if 76 // the session is not opened and a code from MediaErrors.h otherwise. 77 virtual status_t setMediaCasSession(const CasSessionId& sessionId) = 0; 78 79 // If the error returned falls into the range 80 // ERROR_CAS_VENDOR_MIN..ERROR_CAS_VENDOR_MAX, errorDetailMsg should be 81 // filled in with an appropriate string. 82 // At the java level these special errors will then trigger a 83 // MediaCodec.CryptoException that gives clients access to both 84 // the error code and the errorDetailMsg. 85 // Returns a non-negative result to indicate the number of bytes written 86 // to the dstPtr, or a negative result to indicate an error. 87 virtual ssize_t descramble( 88 bool secure, 89 ScramblingControl scramblingControl, 90 size_t numSubSamples, 91 const SubSample *subSamples, 92 const void *srcPtr, 93 int32_t srcOffset, 94 void *dstPtr, 95 int32_t dstOffset, 96 AString *errorDetailMsg) = 0; 97 98 private: 99 DescramblerPlugin(const DescramblerPlugin &); 100 DescramblerPlugin &operator=(const DescramblerPlugin &); 101 }; 102 103 } // namespace android 104 105 extern "C" { 106 extern android::DescramblerFactory *createDescramblerFactory(); 107 } 108 109 #endif // DESCRAMBLER_API_H_ 110