// Copyright 2019 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 <ddk/binding.h>
#include <ddk/debug.h>
#include <ddk/device.h>
#include <ddk/driver.h>
#include <ddk/protocol/ethernet.h>

#include <ddktl/device.h>
#include <ddktl/protocol/empty-protocol.h>
#include <ddktl/protocol/ethernet.h>
#include <fbl/auto_lock.h>
#include <fbl/intrusive_double_list.h>
#include <lib/fidl-utils/bind.h>
#include <lib/fzl/vmo-mapper.h>
#include <lib/zx/fifo.h>

#include <fuchsia/hardware/ethernet/c/fidl.h>

#include <zircon/assert.h>
#include <zircon/device/ethernet.h>
#include <zircon/listnode.h>
#include <zircon/process.h>
#include <zircon/status.h>
#include <zircon/syscalls.h>
#include <zircon/thread_annotations.h>
#include <zircon/types.h>

#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <threads.h>

namespace eth {

class EthDev0;
class EthDev;

struct TransmitInfo {
    EthDev* edev;
    uint64_t fifo_cookie;
    list_node_t node;
};

using EthDev0Type = ddk::Device<EthDev0, ddk::Openable, ddk::Unbindable>;

class EthDev0 : public EthDev0Type,
                public ddk::EmptyProtocol<ZX_PROTOCOL_ETHERNET> {

public:
    EthDev0(zx_device_t* parent)
        : EthDev0Type(parent), mac_(parent) {}

    EthDev0(const EthDev0&) = delete;
    EthDev0(EthDev0&&) = delete;
    EthDev0& operator=(const EthDev0&) = delete;
    EthDev0& operator=(EthDev0&&) = delete;

    static zx_status_t EthBind(void* ctx, zx_device_t* dev);
    zx_status_t DdkOpen(zx_device_t** dev_out, uint32_t flags);
    void DdkUnbind();
    void DdkRelease();

    zx_status_t AddDevice();
    void SetStatus(uint32_t status);
    void Recv(const void* data, size_t len, uint32_t flags);
    void CompleteTx(ethmac_netbuf_t* netbuf, zx_status_t status);

private:
    friend class EthDev;

    // Buffer typecasting functions.
    TransmitInfo* NetbufToTransmitInfo(ethmac_netbuf_t* netbuf);
    ethmac_netbuf_t* TransmitInfoToNetbuf(TransmitInfo* tx_info);
    // Resend transmitted packets for loopback.
    void TransmitEcho(const void* data, size_t len);
    void DestroyAllEthDev();

    ddk::EthmacProtocolClient mac_;
    ethmac_info_t info_ = {};
    uint32_t status_ = 0;

    int32_t promisc_requesters_ = 0;
    int32_t multicast_promisc_requesters_ = 0;

    fbl::Mutex ethdev_lock_;

    // Active and idle instances (EthDev).
    fbl::DoublyLinkedList<EthDev*> list_active_ __TA_GUARDED(ethdev_lock_);
    fbl::DoublyLinkedList<EthDev*> list_idle_ __TA_GUARDED(ethdev_lock_);
};

using EthDevType = ddk::Device<EthDev, ddk::Openable, ddk::Closable, ddk::Messageable>;

class EthDev : public EthDevType,
               public ddk::EmptyProtocol<ZX_PROTOCOL_ETHERNET>,
               public fbl::DoublyLinkedListable<EthDev*> {

public:
    EthDev(zx_device_t* parent, EthDev0* edev0)
        : EthDevType(parent), edev0_(edev0), open_count_(1) {}

    EthDev(const EthDev&) = delete;
    EthDev(EthDev&&) = delete;
    EthDev& operator=(const EthDev&) = delete;
    EthDev& operator=(EthDev&&) = delete;

    zx_status_t DdkOpen(zx_device_t** dev_out, uint32_t flags);
    zx_status_t DdkClose(uint32_t flags);
    void DdkRelease();
    zx_status_t DdkMessage(fidl_msg_t* msg, fidl_txn_t* txn);
    zx_status_t AddDevice(zx_device_t** out);

    // These methods are guarded by EthDev0's ethdev_lock_.
    zx_status_t MsgGetInfoLocked(fidl_txn_t* txn) __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t MsgGetFifosLocked(fidl_txn_t* txn) __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t MsgSetIOBufferLocked(zx_handle_t h, fidl_txn_t* txn)
        __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t MsgStartLocked(fidl_txn_t* txn) __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t MsgStopLocked(fidl_txn_t* txn) __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t MsgListenStartLocked(fidl_txn_t* txn) __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t MsgListenStopLocked(fidl_txn_t* txn) __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t MsgSetClientNameLocked(const char* buf, size_t len,
                                       fidl_txn_t* txn) __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t MsgGetStatusLocked(fidl_txn_t* txn) __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t MsgSetPromiscLocked(bool enabled, fidl_txn_t* txn)
        __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t MsgConfigMulticastAddMacLocked(const fuchsia_hardware_ethernet_MacAddress* mac,
                                               fidl_txn_t* txn) __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t
    MsgConfigMulticastDeleteMacLocked(const fuchsia_hardware_ethernet_MacAddress* mac,
                                      fidl_txn_t* txn) __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t MsgConfigMulticastSetPromiscuousModeLocked(bool enabled,
                                                           fidl_txn_t* txn)
        __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t MsgConfigMulticastTestFilterLocked(fidl_txn_t* txn)
        __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t MsgDumpRegistersLocked(fidl_txn_t* txn)
        __TA_REQUIRES(edev0_->ethdev_lock_);

private:
    friend class EthDev0;

    // Transmit thread has been created.
    static constexpr uint32_t kStateTransmitThreadCreated = (1 << 0);
    // Connected to the ethmac and handling traffic.
    static constexpr uint32_t kStateRunning = (1 << 1);
    // Being destroyed.
    static constexpr uint32_t kStateDead = (1 << 2);
    // This client should loopback tx packets to rx path.
    static constexpr uint32_t kStateTransmissionLoopback = (1 << 3);
    // This client wants to observe loopback tx packets.
    static constexpr uint32_t kStateTransmissionListen = (1 << 4);
    // This client has requested promisc mode.
    static constexpr uint32_t kStatePromiscuous = (1 << 5);
    // This client has requested multicast promisc mode.
    static constexpr uint32_t kStateMulticastPromiscuous = (1 << 6);

    static constexpr uint32_t kFifoDepth = 256;
    static constexpr uint32_t kFifoEntrySize = sizeof(eth_fifo_entry_t);
    static constexpr uint32_t kPageMask = PAGE_SIZE - 1;
    // Ensure that we will not exceed fifo capacity.
    // Limited to one page - see fifo_create.md.
    static_assert((kFifoDepth * kFifoEntrySize) <= 4096, "");
    // Number of empty fifo entries to read at a time.
    static constexpr uint32_t kFifoBatchSize = 32;

    // How many multicast addresses to remember before punting and turning on multicast-promiscuous.
    // TODO(eventually): enable deleting addresses.
    // If this value is changed, change the EthernetMulticastPromiscOnOverflow() test in
    //   zircon/system/utest/ethernet/ethernet.cpp.
    static constexpr uint32_t kMulticastListLimit = 32;

    static constexpr uint32_t kFailureReportRate = 50;

    int TransmitThread();
    zx_status_t PromiscHelperLogicLocked(bool req_on, uint32_t state_bit,
                                         uint32_t param_id, int32_t* requesters_count)
        __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t SetPromiscLocked(bool req_on) __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t SetMulticastPromiscLocked(bool req_on) __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t RebuildMulticastFilterLocked() __TA_REQUIRES(edev0_->ethdev_lock_);
    int MulticastAddressIndex(const uint8_t* mac) __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t AddMulticastAddressLocked(const uint8_t* mac) __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t DelMulticastAddressLocked(const uint8_t* mac) __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t TestClearMulticastPromiscLocked() __TA_REQUIRES(edev0_->ethdev_lock_);

    int TransmitFifoWrite(eth_fifo_entry_t* entries,
                          size_t count);
    TransmitInfo* GetTransmitInfo();
    void PutTransmitInfo(TransmitInfo* tx_info);
    int Send(eth_fifo_entry_t* entries, size_t count);
    void StopAndKill();

    // These methods are guarded by EthDev0's ethdev_lock_.
    void RecvLocked(const void* data, size_t len, uint32_t extra)
        __TA_REQUIRES(edev0_->ethdev_lock_);
    void KillLocked() __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t StopLocked() __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t SetClientNameLocked(const void* in_buf, size_t in_len)
        __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t GetStatusLocked(void* out_buf, size_t out_len,
                                size_t* out_actual) __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t StartLocked() __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t TransmitListenLocked(bool yes) __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t GetFifosLocked(struct fuchsia_hardware_ethernet_Fifos* fifos)
        __TA_REQUIRES(edev0_->ethdev_lock_);
    zx_status_t SetIObufLocked(zx_handle_t vmo) __TA_REQUIRES(edev0_->ethdev_lock_);

    // This is used for signaling that TransmitThread() should exit.
    static const zx_signals_t kSignalFifoTerminate = ZX_USER_SIGNAL_0;

    EthDev0* edev0_ = nullptr;

    uint8_t multicast_[kMulticastListLimit][ETH_MAC_SIZE] = {};
    uint32_t num_multicast_ = 0;

    uint32_t state_ = 0;
    char name_[fuchsia_hardware_ethernet_MAX_CLIENT_NAME_LEN + 1];

    // Fifos are named from the perspective of the packet from the client
    // to the network interface.
    zx::fifo transmit_fifo_;
    uint32_t transmit_fifo_depth_ = 0;
    zx::fifo receive_fifo_;
    uint32_t receive_fifo_depth_ = 0;
    eth_fifo_entry_t receive_fifo_entries_[kFifoBatchSize] = {};
    size_t receive_fifo_entry_count_ = 0;

    // io buffer.
    zx::vmo io_vmo_;
    fzl::VmoMapper io_buffer_;
    fbl::unique_ptr<zx_paddr_t[]> paddr_map_ = nullptr;
    zx::pmt pmt_;

    // kFifoDepth entries, each |transmit_buffer_size_| large.
    fbl::unique_ptr<uint8_t[]> all_transmit_buffers_ = nullptr;
    size_t transmit_buffer_size_ = 0;

    fbl::Mutex lock_;                                            // Protects free_tx_bufs.
    list_node_t free_transmit_buffers_ __TA_GUARDED(lock_) = {}; // TransmitInfo elements.
    uint64_t open_count_ __TA_GUARDED(lock_) = 0;

    // fifo transmit thread.
    thrd_t transmit_thread_ = {};

    uint32_t fail_receive_read_ = 0;
    uint32_t fail_receive_write_ = 0;
    uint32_t ethmac_request_count_ = 0;
    uint32_t ethmac_response_count_ = 0;
};

} // namespace eth