| // Copyright 2017 The Fuchsia Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| #pragma once |
| |
| #include "device.h" |
| #include "ring.h" |
| #include <ddk/io-buffer.h> |
| #include <stdlib.h> |
| #include <zircon/compiler.h> |
| |
| namespace virtio { |
| |
| class Ring; |
| |
| class RngDevice : public Device { |
| public: |
| RngDevice(zx_device_t* bus_device, zx::bti bti, fbl::unique_ptr<Backend> backend); |
| virtual ~RngDevice(); |
| |
| zx_status_t Init() override; |
| |
| void IrqRingUpdate() override; |
| void IrqConfigChange() override; |
| const char* tag() const override { return "virtio-rng"; } |
| |
| protected: |
| private: |
| // TODO(SEC-29): The kernel should trigger entropy requests, instead of relying on this |
| // userspace thread to push entropy whenever it wants to. As a temporary hack, this thread |
| // pushes entropy to the kernel every 300 seconds instead. |
| |
| // the entry point for the entropy seeding thread |
| static int SeedThreadEntry(void* arg); |
| |
| // the method called by SeedThreadEntry() to actually launch a request |
| zx_status_t Request(); |
| |
| // the thread that seeds the system CPRNG periodically |
| thrd_t seed_thread_; |
| |
| // the virtio ring |
| static constexpr uint16_t kRingIndex = 0; |
| static constexpr uint16_t kRingSize = 1; |
| Ring vring_ = {this}; |
| |
| // the buffer used to receive entropy |
| static constexpr size_t kBufferSize = ZX_CPRNG_ADD_ENTROPY_MAX_LEN; |
| io_buffer_t buf_; |
| }; |
| |
| } // namespace virtio |