frame_decryptor_interface.h (3488B)
1 /* 2 * Copyright 2018 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef API_CRYPTO_FRAME_DECRYPTOR_INTERFACE_H_ 12 #define API_CRYPTO_FRAME_DECRYPTOR_INTERFACE_H_ 13 14 #include <cstddef> 15 #include <cstdint> 16 #include <vector> 17 18 #include "api/array_view.h" 19 #include "api/media_types.h" 20 #include "api/ref_count.h" 21 22 namespace webrtc { 23 24 // FrameDecryptorInterface allows users to provide a custom decryption 25 // implementation for all incoming audio and video frames. The user must also 26 // provide a FrameEncryptorInterface to be able to encrypt the frames being 27 // sent out of the device. Note this is an additional layer of encyrption in 28 // addition to the standard SRTP mechanism and is not intended to be used 29 // without it. You may assume that this interface will have the same lifetime 30 // as the RTPReceiver it is attached to. It must only be attached to one 31 // RTPReceiver. Additional data may be null. 32 class FrameDecryptorInterface : public RefCountInterface { 33 public: 34 // The Status enum represents all possible states that can be 35 // returned when attempting to decrypt a frame. kRecoverable indicates that 36 // there was an error with the given frame and so it should not be passed to 37 // the decoder, however it hints that the receive stream is still decryptable 38 // which is important for determining when to send key frame requests 39 // kUnknown should never be returned by the implementor. 40 enum class Status { kOk, kRecoverable, kFailedToDecrypt, kUnknown }; 41 42 struct Result { 43 Result(Status status, size_t bytes_written) 44 : status(status), bytes_written(bytes_written) {} 45 46 bool IsOk() const { return status == Status::kOk; } 47 48 const Status status; 49 const size_t bytes_written; 50 }; 51 52 ~FrameDecryptorInterface() override {} 53 54 // Attempts to decrypt the encrypted frame. You may assume the frame size will 55 // be allocated to the size returned from GetMaxPlaintextSize. You may assume 56 // that the frames are in order if SRTP is enabled. The stream is not provided 57 // here and it is up to the implementor to transport this information to the 58 // receiver if they care about it. You must set bytes_written to how many 59 // bytes you wrote to in the frame buffer. kOk must be returned if successful, 60 // kRecoverable should be returned if the failure was due to something other 61 // than a decryption failure. kFailedToDecrypt should be returned in all other 62 // cases. 63 virtual Result Decrypt(MediaType media_type, 64 const std::vector<uint32_t>& csrcs, 65 ArrayView<const uint8_t> additional_data, 66 ArrayView<const uint8_t> encrypted_frame, 67 ArrayView<uint8_t> frame) = 0; 68 69 // Returns the total required length in bytes for the output of the 70 // decryption. This can be larger than the actual number of bytes you need but 71 // must never be smaller as it informs the size of the frame buffer. 72 virtual size_t GetMaxPlaintextByteSize(MediaType media_type, 73 size_t encrypted_frame_size) = 0; 74 }; 75 76 } // namespace webrtc 77 78 #endif // API_CRYPTO_FRAME_DECRYPTOR_INTERFACE_H_