media_channel_impl.h

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/*

 *  Copyright 2022 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 MEDIA_BASE_MEDIA_CHANNEL_IMPL_H_

#define MEDIA_BASE_MEDIA_CHANNEL_IMPL_H_

#include <stddef.h>

#include <stdint.h>

#include "api/array_view.h"

#include "api/call/transport.h"

#include "api/scoped_refptr.h"

#include "api/sequence_checker.h"

#include "api/task_queue/pending_task_safety_flag.h"

#include "api/task_queue/task_queue_base.h"

#include "media/base/media_channel.h"

#include "rtc_base/async_packet_socket.h"

#include "rtc_base/copy_on_write_buffer.h"

#include "rtc_base/dscp.h"

#include "rtc_base/socket.h"

#include "rtc_base/thread_annotations.h"

// This file contains the base classes for classes that implement

// the channel interfaces.

// These implementation classes used to be the exposed interface names,

// but this is in the process of being changed.

namespace webrtc {

// The `MediaChannelUtil` class provides functionality that is used by

// multiple MediaChannel-like objects, of both sending and receiving

// types.

class MediaChannelUtil {

 public:

  explicit MediaChannelUtil(TaskQueueBase* network_thread,

                            bool enable_dscp = false);

  virtual ~MediaChannelUtil();

  // Returns the absolute sendtime extension id value from media channel.

  virtual int GetRtpSendTimeExtnId() const;

  Transport* transport() { return &transport_; }

  // Base methods to send packet using MediaChannelNetworkInterface.

  // These methods are used by some tests only.

  bool SendPacket(CopyOnWriteBuffer* packet,

                  const AsyncSocketPacketOptions& options);

  bool SendRtcp(CopyOnWriteBuffer* packet,

                const AsyncSocketPacketOptions& options);

  int SetOption(MediaChannelNetworkInterface::SocketType type,

                Socket::Option opt,

                int option);

  // Functions that form part of one or more interface classes.

  // Not marked override, since this class does not inherit from the

  // interfaces.

  // Corresponds to the SDP attribute extmap-allow-mixed, see RFC8285.

  // Set to true if it's allowed to mix one- and two-byte RTP header extensions

  // in the same stream. The setter and getter must only be called from

  // worker_thread.

  void SetExtmapAllowMixed(bool extmap_allow_mixed);

  bool ExtmapAllowMixed() const;

  void SetInterface(MediaChannelNetworkInterface* iface);

  // Returns `true` if a non-null MediaChannelNetworkInterface pointer is held.

  // Must be called on the network thread.

  bool HasNetworkInterface() const;

 protected:

  bool DscpEnabled() const;

  void SetPreferredDscp(DiffServCodePoint new_dscp);

 private:

  // Implementation of the webrtc::Transport interface required

  // by Call().

  class TransportForMediaChannels : public Transport {

   public:

    TransportForMediaChannels(TaskQueueBase* network_thread, bool enable_dscp);

    virtual ~TransportForMediaChannels();

    // Implementation of webrtc::Transport

    bool SendRtp(ArrayView<const uint8_t> packet,

                 const PacketOptions& options) override;

    bool SendRtcp(ArrayView<const uint8_t> packet,

                  const PacketOptions& options) override;

    // Not implementation of webrtc::Transport

    void SetInterface(MediaChannelNetworkInterface* iface);

    int SetOption(MediaChannelNetworkInterface::SocketType type,

                  Socket::Option opt,

                  int option);

    AsyncSocketPacketOptions TranslatePacketOptions(

        const PacketOptions& options);

    bool DoSendPacket(CopyOnWriteBuffer* packet,

                      bool rtcp,

                      const AsyncSocketPacketOptions& options);

    bool HasNetworkInterface() const {

      RTC_DCHECK_RUN_ON(network_thread_);

      return network_interface_ != nullptr;

    bool DscpEnabled() const { return enable_dscp_; }

    void SetPreferredDscp(DiffServCodePoint new_dscp);

   private:

    // This is the DSCP value used for both RTP and RTCP channels if DSCP is

    // enabled. It can be changed at any time via `SetPreferredDscp`.

    DiffServCodePoint PreferredDscp() const {

      RTC_DCHECK_RUN_ON(network_thread_);

      return preferred_dscp_;

    // Apply the preferred DSCP setting to the underlying network interface RTP

    // and RTCP channels. If DSCP is disabled, then apply the default DSCP

    // value.

    void UpdateDscp() RTC_RUN_ON(network_thread_);

    int SetOptionLocked(MediaChannelNetworkInterface::SocketType type,

                        Socket::Option opt,

                        int option) RTC_RUN_ON(network_thread_);

    const scoped_refptr<PendingTaskSafetyFlag> network_safety_

        RTC_PT_GUARDED_BY(network_thread_);

    TaskQueueBase* const network_thread_;

    const bool enable_dscp_;

    MediaChannelNetworkInterface* network_interface_

        RTC_GUARDED_BY(network_thread_) = nullptr;

    DiffServCodePoint preferred_dscp_ RTC_GUARDED_BY(network_thread_) =

        webrtc::DSCP_DEFAULT;

};

  bool extmap_allow_mixed_ = false;

  TransportForMediaChannels transport_;

};

}  // namespace webrtc

#endif  // MEDIA_BASE_MEDIA_CHANNEL_IMPL_H_