data_channel_controller.h

/*

 *  Copyright 2019 The WebRTC project authors. All Rights Reserved.

 *  Use of this source code is governed by a BSD-style license

 *  that can be found in the LICENSE file in the root of the source

 *  tree. An additional intellectual property rights grant can be found

 *  in the file PATENTS.  All contributing project authors may

 *  be found in the AUTHORS file in the root of the source tree.

*/

#ifndef PC_DATA_CHANNEL_CONTROLLER_H_

#define PC_DATA_CHANNEL_CONTROLLER_H_

#include <string>

#include <vector>

#include "api/data_channel_interface.h"

#include "api/priority.h"

#include "api/rtc_error.h"

#include "api/scoped_refptr.h"

#include "api/sequence_checker.h"

#include "api/task_queue/pending_task_safety_flag.h"

#include "api/transport/data_channel_transport_interface.h"

#include "pc/data_channel_utils.h"

#include "pc/sctp_data_channel.h"

#include "rtc_base/checks.h"

#include "rtc_base/copy_on_write_buffer.h"

#include "rtc_base/ssl_stream_adapter.h"

#include "rtc_base/thread.h"

#include "rtc_base/thread_annotations.h"

#include "rtc_base/weak_ptr.h"

namespace webrtc {

class PeerConnectionInternal;

class DataChannelController : public SctpDataChannelControllerInterface,

                              public DataChannelSink {

 public:

  explicit DataChannelController(PeerConnectionInternal* pc) : pc_(pc) {}

  ~DataChannelController();

  // Not copyable or movable.

  DataChannelController(DataChannelController&) = delete;

  DataChannelController& operator=(const DataChannelController& other) = delete;

  DataChannelController(DataChannelController&&) = delete;

  DataChannelController& operator=(DataChannelController&& other) = delete;

  // Implements

  // SctpDataChannelProviderInterface.

  RTCError SendData(StreamId sid,

                    const SendDataParams& params,

                    const rtc::CopyOnWriteBuffer& payload) override;

  void AddSctpDataStream(StreamId sid, PriorityValue priority) override;

  void RemoveSctpDataStream(StreamId sid) override;

  void OnChannelStateChanged(SctpDataChannel* channel,

                             DataChannelInterface::DataState state) override;

  size_t buffered_amount(StreamId sid) const override;

  size_t buffered_amount_low_threshold(StreamId sid) const override;

  void SetBufferedAmountLowThreshold(StreamId sid, size_t bytes) override;

  // Implements DataChannelSink.

  void OnDataReceived(int channel_id,

                      DataMessageType type,

                      const rtc::CopyOnWriteBuffer& buffer) override;

  void OnChannelClosing(int channel_id) override;

  void OnChannelClosed(int channel_id) override;

  void OnReadyToSend() override;

  void OnTransportClosed(RTCError error) override;

  void OnBufferedAmountLow(int channel_id) override;

  // Called as part of destroying the owning PeerConnection.

  void PrepareForShutdown();

  // Called from PeerConnection::SetupDataChannelTransport_n

  void SetupDataChannelTransport_n(DataChannelTransportInterface* transport);

  // Called from PeerConnection::TeardownDataChannelTransport_n

  void TeardownDataChannelTransport_n(RTCError error);

  // Called from PeerConnection::OnTransportChanged

  // to make required changes to datachannels' transports.

  void OnTransportChanged(

      DataChannelTransportInterface* data_channel_transport);

  // Called from PeerConnection::GetDataChannelStats on the signaling thread.

  std::vector<DataChannelStats> GetDataChannelStats() const;

  // Creates channel and adds it to the collection of DataChannels that will

  // be offered in a SessionDescription, and wraps it in a proxy object.

  RTCErrorOr<rtc::scoped_refptr<DataChannelInterface>>

  InternalCreateDataChannelWithProxy(const std::string& label,

                                     const InternalDataChannelInit& config);

  void AllocateSctpSids(rtc::SSLRole role);

  // Check if data channels are currently tracked. Used to decide whether a

  // rejected m=application section should be reoffered.

  bool HasDataChannels() const;

  // At some point in time, a data channel has existed.

  bool HasUsedDataChannels() const;

 protected:

  rtc::Thread* network_thread() const;

  rtc::Thread* signaling_thread() const;

 private:

  void OnSctpDataChannelClosed(SctpDataChannel* channel);

  // Creates a new SctpDataChannel object on the network thread.

  RTCErrorOr<rtc::scoped_refptr<SctpDataChannel>> CreateDataChannel(

      const std::string& label,

      InternalDataChannelInit& config) RTC_RUN_ON(network_thread());

  // Parses and handles open messages.  Returns true if the message is an open

  // message and should be considered to be handled, false otherwise.

  bool HandleOpenMessage_n(int channel_id,

                           DataMessageType type,

                           const rtc::CopyOnWriteBuffer& buffer)

      RTC_RUN_ON(network_thread());

  // Called when a valid data channel OPEN message is received.

  void OnDataChannelOpenMessage(rtc::scoped_refptr<SctpDataChannel> channel,

                                bool ready_to_send)

      RTC_RUN_ON(signaling_thread());

  // Accepts a `StreamId` which may be pre-negotiated or unassigned. For

  // pre-negotiated sids, attempts to reserve the sid in the allocation pool,

  // for unassigned sids attempts to generate a new sid if possible. Returns

  // RTCError::OK() if the sid is reserved (and may have been generated) or

  // if not enough information exists to generate a sid, in which case the sid

  // will still be unassigned upon return, but will be assigned later.

  // If the pool has been exhausted or a sid has already been reserved, an

  // error will be returned.

  RTCError ReserveOrAllocateSid(absl::optional<StreamId>& sid,

                                absl::optional<rtc::SSLRole> fallback_ssl_role)

      RTC_RUN_ON(network_thread());

  // Called when all data channels need to be notified of a transport channel

  // (calls OnTransportChannelCreated on the signaling thread).

  void NotifyDataChannelsOfTransportCreated();

  void set_data_channel_transport(DataChannelTransportInterface* transport);

  // Plugin transport used for data channels.  Pointer may be accessed and

  // checked from any thread, but the object may only be touched on the

  // network thread.

  DataChannelTransportInterface* data_channel_transport_

      RTC_GUARDED_BY(network_thread()) = nullptr;

  SctpSidAllocator sid_allocator_ RTC_GUARDED_BY(network_thread());

  std::vector<rtc::scoped_refptr<SctpDataChannel>> sctp_data_channels_n_

      RTC_GUARDED_BY(network_thread());

  enum class DataChannelUsage : uint8_t {

    kNeverUsed = 0,

    kHaveBeenUsed,

    kInUse

};

  DataChannelUsage channel_usage_ RTC_GUARDED_BY(signaling_thread()) =

      DataChannelUsage::kNeverUsed;

  // Owning PeerConnection.

  PeerConnectionInternal* const pc_;

  // The weak pointers must be dereferenced and invalidated on the network

  // thread only.

  rtc::WeakPtrFactory<DataChannelController> weak_factory_

      RTC_GUARDED_BY(network_thread()){this};

  ScopedTaskSafety signaling_safety_;

};

}  // namespace webrtc

#endif  // PC_DATA_CHANNEL_CONTROLLER_H_