Add QuicDataChannel and QuicDataTransport classes

webrtc/api/quicdatachannel.h

+/*
+ *  Copyright 2016 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 WEBRTC_API_QUICDATACHANNEL_H_
+#define WEBRTC_API_QUICDATACHANNEL_H_
+
+#include <string>
+#include <unordered_map>
+#include <unordered_set>
+
+#include "webrtc/api/datachannelinterface.h"
+#include "webrtc/base/asyncinvoker.h"
+#include "webrtc/base/sigslot.h"
+#include "webrtc/base/thread.h"
+
+namespace cricket {
+class QuicTransportChannel;
+class ReliableQuicStream;
+class TransportChannel;
+}  // namepsace cricket
+
+namespace net {
+// TODO(mikescarlett): Make this uint64_t once QUIC uses 64-bit ids.
+typedef uint32_t QuicStreamId;
+}  // namespace net
+
+namespace rtc {
+class CopyOnWriteBuffer;
+}  // namespace rtc
+
+namespace webrtc {
+
+// Encodes a QUIC message header with the data channel ID and message ID, then
+// stores the result in |header|.
+void WriteQuicDataChannelMessageHeader(int data_channel_id,
+                                       uint64_t message_id,
+                                       rtc::CopyOnWriteBuffer* header);
+
+// Decodes the data channel ID and message ID from the initial data received by
+// an incoming QUIC stream. The data channel ID is output to |data_channel_id|,
+// the message ID is output to |message_id|, and the number of bytes read is
+// output to |bytes_read|. Returns false if either ID cannot be read.
+bool ParseQuicDataMessageHeader(const char* data,
+                                size_t len,
+                                int* data_channel_id,
+                                uint64_t* message_id,
+                                size_t* bytes_read);
+
+// QuicDataChannel is an implementation of DataChannelInterface based on the
+// QUIC protocol. It uses a QuicTransportChannel to establish encryption and
+// transfer data, and a QuicDataTransport to receive incoming messages at
+// the correct data channel. Currently this class implements unordered, reliable
+// delivery and does not send an "OPEN" message.
+//
+// Each time a message is sent:
+//
+// - The QuicDataChannel prepends it with the data channel id and message id.
+//   The QuicTransportChannel creates a ReliableQuicStream, then the
+//   ReliableQuicStream sends the message with a FIN.
+//
+// - The remote QuicSession creates a ReliableQuicStream to receive the data.
+//   The remote QuicDataTransport dispatches the ReliableQuicStream to the
+//   QuicDataChannel with the same id as this data channel.
+//
+// - The remote QuicDataChannel queues data from the ReliableQuicStream. Once
+//   it receives a QUIC stream frame with a FIN, it provides the message to the
+//   DataChannelObserver.
+//
+// TODO(mikescarlett): Implement ordered delivery, unreliable delivery, and
+// an OPEN message similar to the one for SCTP.
+class QuicDataChannel : public rtc::RefCountedObject<DataChannelInterface>,
+                        public sigslot::has_slots<> {
+ public:
+  // Message stores buffered data from the incoming QUIC stream. The QUIC stream
+  // is provided so that remaining data can be received from the remote peer.
+  struct Message {
+    uint64_t id;
+    rtc::CopyOnWriteBuffer buffer;
+    cricket::ReliableQuicStream* stream;
+  };
+
+  QuicDataChannel(rtc::Thread* signaling_thread,
+                  rtc::Thread* worker_thread,
+                  const std::string& label,
+                  const DataChannelInit& config);
+  ~QuicDataChannel() override;
+
+  // DataChannelInterface overrides.
+  std::string label() const override { return label_; }
+  bool reliable() const override { return true; }
+  bool ordered() const override { return false; }
+  uint16_t maxRetransmitTime() const override { return -1; }
+  uint16_t maxRetransmits() const override { return -1; }
+  bool negotiated() const override { return false; }
+  int id() const override { return id_; }
+  DataState state() const override { return state_; }
+  uint64_t buffered_amount() const override { return buffered_amount_; }
+  std::string protocol() const override { return protocol_; }
+  void RegisterObserver(DataChannelObserver* observer) override;
+  void UnregisterObserver() override;
+  void Close() override;
+  bool Send(const DataBuffer& buffer) override;
+
+  // Called from QuicDataTransport to set the QUIC transport channel that the
+  // QuicDataChannel sends messages with. Returns false if a different QUIC
+  // transport channel is already set or |channel| is NULL.
+  //
+  // The QUIC transport channel is not set in the constructor to allow creating
+  // the QuicDataChannel before the PeerConnection has a QUIC transport channel,
+  // such as before the session description is not set.
+  bool SetTransportChannel(cricket::QuicTransportChannel* channel);
+
+  // Called from QuicDataTransport when an incoming ReliableQuicStream is
+  // receiving a message received for this data channel. Once this function is
+  // called, |message| is owned by the QuicDataChannel and should not be
+  // accessed by the QuicDataTransport.
+  void OnIncomingMessage(Message&& message);
+
+  // Methods for testing.
+  // Gets the number of outgoing QUIC streams with write blocked data that are
+  // currently open for this data channel and are not finished writing a
+  // message. This is equivalent to the size of |write_blocked_quic_streams_|.
+  size_t GetNumWriteBlockedStreams() const;
+  // Gets the number of incoming QUIC streams with buffered data that are
+  // currently open for this data channel and are not finished receiving a
+  // message. This is equivalent to the size of |incoming_quic_messages_|.
+  size_t GetNumIncomingStreams() const;
+
+ private:
+  // Callbacks from ReliableQuicStream.
+  // Called when an incoming QUIC stream in |incoming_quic_messages_| has
+  // received a QUIC stream frame.
+  void OnDataReceived(net::QuicStreamId stream_id,
+                      const char* data,
+                      size_t len);
+  // Called when a write blocked QUIC stream that has been added to
+  // |write_blocked_quic_streams_| is closed.
+  void OnWriteBlockedStreamClosed(net::QuicStreamId stream_id, int error);
+  // Called when an incoming QUIC stream that has been added to
+  // |incoming_quic_messages_| is closed.
+  void OnIncomingQueuedStreamClosed(net::QuicStreamId stream_id, int error);
+  // Called when a write blocked QUIC stream in |write_blocked_quic_streams_|
+  // has written previously queued data.
+  void OnQueuedBytesWritten(net::QuicStreamId stream_id,
+                            uint64_t queued_bytes_written);
+
+  // Callbacks from |quic_transport_channel_|.
+  void OnReadyToSend(cricket::TransportChannel* channel);
+  void OnConnectionClosed();
+
+  // Worker thread methods.
+  // Sends the data buffer to the remote peer using an outgoing QUIC stream.
+  // Returns true if the data buffer can be successfully sent, or if it is
+  // queued to be sent later.
+  bool Send_w(const DataBuffer& buffer);
+  // Connects the |quic_transport_channel_| signals to this QuicDataChannel,
+  // then returns the new QuicDataChannel state.
+  DataState SetTransportChannel_w();
+  // Closes the QUIC streams associated with this QuicDataChannel.
+  void Close_w();
+  // Sets |buffered_amount_|.
+  void SetBufferedAmount_w(uint64_t buffered_amount);
+
+  // Signaling thread methods.
+  // Triggers QuicDataChannelObserver::OnMessage when a message from the remote
+  // peer is ready to be read.
+  void OnMessage_s(const DataBuffer& received_data);
+  // Triggers QuicDataChannel::OnStateChange if the state change is valid.
+  // Otherwise does nothing if |state| == |state_| or |state| != kClosed when
+  // the data channel is closing.
+  void SetState_s(DataState state);
+  // Triggers QuicDataChannelObserver::OnBufferedAmountChange when the total
+  // buffered data changes for a QUIC stream.
+  void OnBufferedAmountChange_s(uint64_t buffered_amount);
+
+  // QUIC transport channel which owns the QUIC session. It is used to create
+  // a QUIC stream for sending outgoing messages.
+  cricket::QuicTransportChannel* quic_transport_channel_ = nullptr;
+  // Signaling thread for DataChannelInterface methods.
+  rtc::Thread* const signaling_thread_;
+  // Worker thread for sending data and |quic_transport_channel_| callbacks.
+  rtc::Thread* const worker_thread_;
+  rtc::AsyncInvoker invoker_;
+  // Map of QUIC stream ID => ReliableQuicStream* for write blocked QUIC
+  // streams.
+  std::unordered_map<net::QuicStreamId, cricket::ReliableQuicStream*>
+      write_blocked_quic_streams_;
+  // Map of QUIC stream ID => Message for each incoming QUIC stream.
+  std::unordered_map<net::QuicStreamId, Message> incoming_quic_messages_;
+  // Handles received data from the remote peer and data channel state changes.
+  DataChannelObserver* observer_ = nullptr;
+  // QuicDataChannel ID.
+  int id_;
+  // Connectivity state of the QuicDataChannel.
+  DataState state_;
+  // Total bytes that are buffered among the QUIC streams.
+  uint64_t buffered_amount_;
+  // Counter for number of sent messages that is used for message IDs.
+  uint64_t next_message_id_;
+
+  // Variables for application use.
+  const std::string& label_;
+  const std::string& protocol_;
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_API_QUICDATACHANNEL_H_