722875f72e
Bug: None Change-Id: I590e28acbd17b45dcb4e3bac34d223ad0903f7dc Reviewed-on: https://webrtc-review.googlesource.com/c/113131 Commit-Queue: Philip Eliasson <philipel@webrtc.org> Reviewed-by: Philip Eliasson <philipel@webrtc.org> Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org> Reviewed-by: Danil Chapovalov <danilchap@webrtc.org> Cr-Commit-Position: refs/heads/master@{#25921}
104 lines
3.9 KiB
C++
104 lines
3.9 KiB
C++
/*
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* Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "video/buffered_frame_decryptor.h"
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#include <utility>
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#include "rtc_base/logging.h"
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#include "rtc_base/system/fallthrough.h"
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namespace webrtc {
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BufferedFrameDecryptor::BufferedFrameDecryptor(
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OnDecryptedFrameCallback* decrypted_frame_callback,
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rtc::scoped_refptr<FrameDecryptorInterface> frame_decryptor)
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: frame_decryptor_(std::move(frame_decryptor)),
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decrypted_frame_callback_(decrypted_frame_callback) {}
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BufferedFrameDecryptor::~BufferedFrameDecryptor() {}
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void BufferedFrameDecryptor::ManageEncryptedFrame(
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std::unique_ptr<video_coding::RtpFrameObject> encrypted_frame) {
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switch (DecryptFrame(encrypted_frame.get())) {
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case FrameDecision::kStash:
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if (stashed_frames_.size() >= kMaxStashedFrames) {
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stashed_frames_.pop_front();
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}
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stashed_frames_.push_back(std::move(encrypted_frame));
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break;
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case FrameDecision::kDecrypted:
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RetryStashedFrames();
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decrypted_frame_callback_->OnDecryptedFrame(std::move(encrypted_frame));
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break;
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case FrameDecision::kDrop:
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break;
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}
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}
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BufferedFrameDecryptor::FrameDecision BufferedFrameDecryptor::DecryptFrame(
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video_coding::RtpFrameObject* frame) {
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// Optionally attempt to decrypt the raw video frame if it was provided.
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if (frame_decryptor_ == nullptr) {
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RTC_LOG(LS_WARNING) << "Frame decryption required but not attached to this "
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"stream. Dropping frame.";
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return FrameDecision::kDrop;
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}
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// When using encryption we expect the frame to have the generic descriptor.
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absl::optional<RtpGenericFrameDescriptor> descriptor =
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frame->GetGenericFrameDescriptor();
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if (!descriptor) {
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RTC_LOG(LS_ERROR) << "No generic frame descriptor found dropping frame.";
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return FrameDecision::kDrop;
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}
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// Retrieve the bitstream of the encrypted video frame.
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rtc::ArrayView<const uint8_t> encrypted_frame_bitstream(frame->Buffer(),
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frame->size());
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// Retrieve the maximum possible size of the decrypted payload.
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const size_t max_plaintext_byte_size =
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frame_decryptor_->GetMaxPlaintextByteSize(cricket::MEDIA_TYPE_VIDEO,
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frame->size());
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RTC_CHECK_LE(max_plaintext_byte_size, frame->size());
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// Place the decrypted frame inline into the existing frame.
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rtc::ArrayView<uint8_t> inline_decrypted_bitstream(frame->MutableBuffer(),
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max_plaintext_byte_size);
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// Attempt to decrypt the video frame.
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size_t bytes_written = 0;
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if (frame_decryptor_->Decrypt(
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cricket::MEDIA_TYPE_VIDEO, /*csrcs=*/{},
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descriptor->GetByteRepresentation(), encrypted_frame_bitstream,
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inline_decrypted_bitstream, &bytes_written) != 0) {
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// Only stash frames if we have never decrypted a frame before.
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return first_frame_decrypted_ ? FrameDecision::kDrop
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: FrameDecision::kStash;
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}
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RTC_CHECK_LE(bytes_written, max_plaintext_byte_size);
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// Update the frame to contain just the written bytes.
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frame->SetSize(bytes_written);
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// Indicate that all future fail to decrypt frames should be dropped.
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if (!first_frame_decrypted_) {
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first_frame_decrypted_ = true;
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}
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return FrameDecision::kDecrypted;
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}
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void BufferedFrameDecryptor::RetryStashedFrames() {
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for (auto& frame : stashed_frames_) {
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if (DecryptFrame(frame.get()) == FrameDecision::kDecrypted) {
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decrypted_frame_callback_->OnDecryptedFrame(std::move(frame));
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}
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}
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stashed_frames_.clear();
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}
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} // namespace webrtc
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