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 <vector> 15 16 #include "api/array_view.h" 17 #include "api/media_types.h" 18 #include "rtc_base/ref_count.h" 19 20 namespace webrtc { 21 22 // FrameDecryptorInterface allows users to provide a custom decryption 23 // implementation for all incoming audio and video frames. The user must also 24 // provide a FrameEncryptorInterface to be able to encrypt the frames being 25 // sent out of the device. Note this is an additional layer of encyrption in 26 // addition to the standard SRTP mechanism and is not intended to be used 27 // without it. You may assume that this interface will have the same lifetime 28 // as the RTPReceiver it is attached to. It must only be attached to one 29 // RTPReceiver. Additional data may be null. 30 // Note: This interface is not ready for production use. 31 class FrameDecryptorInterface : public rtc::RefCountInterface { 32 public: 33 // The Status enum represents all possible states that can be 34 // returned when attempting to decrypt a frame. kRecoverable indicates that 35 // there was an error with the given frame and so it should not be passed to 36 // the decoder, however it hints that the receive stream is still decryptable 37 // which is important for determining when to send key frame requests 38 // kUnknown should never be returned by the implementor. 39 enum class Status { kOk, kRecoverable, kFailedToDecrypt, kUnknown }; 40 41 struct Result { ResultResult42 Result(Status status, size_t bytes_written) 43 : status(status), bytes_written(bytes_written) {} 44 IsOkResult45 bool IsOk() const { return status == Status::kOk; } 46 47 const Status status; 48 const size_t bytes_written; 49 }; 50 ~FrameDecryptorInterface()51 ~FrameDecryptorInterface() override {} 52 53 // Attempts to decrypt the encrypted frame. You may assume the frame size will 54 // be allocated to the size returned from GetMaxPlaintextSize. You may assume 55 // that the frames are in order if SRTP is enabled. The stream is not provided 56 // here and it is up to the implementor to transport this information to the 57 // receiver if they care about it. You must set bytes_written to how many 58 // bytes you wrote to in the frame buffer. kOk must be returned if successful, 59 // kRecoverable should be returned if the failure was due to something other 60 // than a decryption failure. kFailedToDecrypt should be returned in all other 61 // cases. 62 virtual Result Decrypt(cricket::MediaType media_type, 63 const std::vector<uint32_t>& csrcs, 64 rtc::ArrayView<const uint8_t> additional_data, 65 rtc::ArrayView<const uint8_t> encrypted_frame, 66 rtc::ArrayView<uint8_t> frame) = 0; 67 68 // Returns the total required length in bytes for the output of the 69 // decryption. This can be larger than the actual number of bytes you need but 70 // must never be smaller as it informs the size of the frame buffer. 71 virtual size_t GetMaxPlaintextByteSize(cricket::MediaType media_type, 72 size_t encrypted_frame_size) = 0; 73 }; 74 75 } // namespace webrtc 76 77 #endif // API_CRYPTO_FRAME_DECRYPTOR_INTERFACE_H_ 78