| // Copyright 2014 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef QUICHE_QUIC_CORE_QUIC_FLOW_CONTROLLER_H_ |
| #define QUICHE_QUIC_CORE_QUIC_FLOW_CONTROLLER_H_ |
| |
| #include "quiche/quic/core/quic_packets.h" |
| #include "quiche/quic/platform/api/quic_export.h" |
| |
| namespace quic { |
| |
| namespace test { |
| class QuicFlowControllerPeer; |
| } // namespace test |
| |
| class QuicConnection; |
| class QuicSession; |
| |
| // How much larger the session flow control window needs to be relative to any |
| // stream's flow control window. |
| inline constexpr float kSessionFlowControlMultiplier = 1.5; |
| |
| class QUICHE_EXPORT QuicFlowControllerInterface { |
| public: |
| virtual ~QuicFlowControllerInterface() {} |
| |
| // Ensures the flow control window is at least |window_size| and send out an |
| // update frame if it is increased. |
| virtual void EnsureWindowAtLeast(QuicByteCount window_size) = 0; |
| }; |
| |
| // QuicFlowController allows a QUIC stream or connection to perform flow |
| // control. The stream/connection owns a QuicFlowController which keeps track of |
| // bytes sent/received, can tell the owner if it is flow control blocked, and |
| // can send WINDOW_UPDATE or BLOCKED frames when needed. |
| class QUICHE_EXPORT QuicFlowController : public QuicFlowControllerInterface { |
| public: |
| QuicFlowController(QuicSession* session, QuicStreamId id, |
| bool is_connection_flow_controller, |
| QuicStreamOffset send_window_offset, |
| QuicStreamOffset receive_window_offset, |
| QuicByteCount receive_window_size_limit, |
| bool should_auto_tune_receive_window, |
| QuicFlowControllerInterface* session_flow_controller); |
| |
| QuicFlowController(const QuicFlowController&) = delete; |
| QuicFlowController(QuicFlowController&&) = default; |
| QuicFlowController& operator=(const QuicFlowController&) = delete; |
| |
| ~QuicFlowController() override {} |
| |
| // Called when we see a new highest received byte offset from the peer, either |
| // via a data frame or a RST. |
| // Returns true if this call changes highest_received_byte_offset_, and false |
| // in the case where |new_offset| is <= highest_received_byte_offset_. |
| bool UpdateHighestReceivedOffset(QuicStreamOffset new_offset); |
| |
| // Called when bytes received from the peer are consumed locally. This may |
| // trigger the sending of a WINDOW_UPDATE frame using |connection|. |
| void AddBytesConsumed(QuicByteCount bytes_consumed); |
| |
| // Called when bytes are sent to the peer. |
| void AddBytesSent(QuicByteCount bytes_sent); |
| |
| // Increases |send_window_offset_| if |new_send_window_offset| is |
| // greater than the current value. Returns true if this increase |
| // also causes us to change from a blocked state to unblocked. In |
| // all other cases, returns false. |
| bool UpdateSendWindowOffset(QuicStreamOffset new_send_window_offset); |
| |
| // QuicFlowControllerInterface. |
| void EnsureWindowAtLeast(QuicByteCount window_size) override; |
| |
| // Returns the current available send window. |
| QuicByteCount SendWindowSize() const; |
| |
| QuicByteCount receive_window_size() const { return receive_window_size_; } |
| |
| // Sends a BLOCKED frame if needed. |
| void MaybeSendBlocked(); |
| |
| // Returns true if flow control send limits have been reached. |
| bool IsBlocked() const; |
| |
| // Returns true if flow control receive limits have been violated by the peer. |
| bool FlowControlViolation(); |
| |
| // Inform the peer of new receive window. |
| void SendWindowUpdate(); |
| |
| QuicByteCount bytes_consumed() const { return bytes_consumed_; } |
| |
| QuicByteCount bytes_sent() const { return bytes_sent_; } |
| |
| QuicStreamOffset send_window_offset() const { return send_window_offset_; } |
| |
| QuicStreamOffset highest_received_byte_offset() const { |
| return highest_received_byte_offset_; |
| } |
| |
| void set_receive_window_size_limit(QuicByteCount receive_window_size_limit) { |
| QUICHE_DCHECK_GE(receive_window_size_limit, receive_window_size_limit_); |
| receive_window_size_limit_ = receive_window_size_limit; |
| } |
| |
| // Should only be called before any data is received. |
| void UpdateReceiveWindowSize(QuicStreamOffset size); |
| |
| bool auto_tune_receive_window() { return auto_tune_receive_window_; } |
| |
| private: |
| friend class test::QuicFlowControllerPeer; |
| |
| // Send a WINDOW_UPDATE frame if appropriate. |
| void MaybeSendWindowUpdate(); |
| |
| // Auto-tune the max receive window size. |
| void MaybeIncreaseMaxWindowSize(); |
| |
| // Updates the current offset and sends a window update frame. |
| void UpdateReceiveWindowOffsetAndSendWindowUpdate( |
| QuicStreamOffset available_window); |
| |
| // Double the window size as long as we haven't hit the max window size. |
| void IncreaseWindowSize(); |
| |
| // Returns "stream $ID" (where $ID is set to |id_|) or "connection" based on |
| // |is_connection_flow_controller_|. |
| std::string LogLabel(); |
| |
| // The parent session/connection, used to send connection close on flow |
| // control violation, and WINDOW_UPDATE and BLOCKED frames when appropriate. |
| // Not owned. |
| QuicSession* session_; |
| QuicConnection* connection_; |
| |
| // ID of stream this flow controller belongs to. If |
| // |is_connection_flow_controller_| is false, this must be a valid stream ID. |
| QuicStreamId id_; |
| |
| // Whether this flow controller is the connection level flow controller |
| // instead of the flow controller for a stream. If true, |id_| is ignored. |
| bool is_connection_flow_controller_; |
| |
| // Tracks if this is owned by a server or a client. |
| Perspective perspective_; |
| |
| // Tracks number of bytes sent to the peer. |
| QuicByteCount bytes_sent_; |
| |
| // The absolute offset in the outgoing byte stream. If this offset is reached |
| // then we become flow control blocked until we receive a WINDOW_UPDATE. |
| QuicStreamOffset send_window_offset_; |
| |
| // Overview of receive flow controller. |
| // |
| // 0=...===1=======2-------3 ...... FIN |
| // |<--- <= 4 --->| |
| // |
| |
| // 1) bytes_consumed_ - moves forward when data is read out of the |
| // stream. |
| // |
| // 2) highest_received_byte_offset_ - moves when data is received |
| // from the peer. |
| // |
| // 3) receive_window_offset_ - moves when WINDOW_UPDATE is sent. |
| // |
| // 4) receive_window_size_ - maximum allowed unread data (3 - 1). |
| // This value may be increased by auto-tuning. |
| // |
| // 5) receive_window_size_limit_ - limit on receive_window_size_; |
| // auto-tuning will not increase window size beyond this limit. |
| |
| // Track number of bytes received from the peer, which have been consumed |
| // locally. |
| QuicByteCount bytes_consumed_; |
| |
| // The highest byte offset we have seen from the peer. This could be the |
| // highest offset in a data frame, or a final value in a RST. |
| QuicStreamOffset highest_received_byte_offset_; |
| |
| // The absolute offset in the incoming byte stream. The peer should never send |
| // us bytes which are beyond this offset. |
| QuicStreamOffset receive_window_offset_; |
| |
| // Largest size the receive window can grow to. |
| QuicByteCount receive_window_size_; |
| |
| // Upper limit on receive_window_size_; |
| QuicByteCount receive_window_size_limit_; |
| |
| // Used to dynamically enable receive window auto-tuning. |
| bool auto_tune_receive_window_; |
| |
| // The session's flow controller. Null if this is the session flow controller. |
| // Not owned. |
| QuicFlowControllerInterface* session_flow_controller_; |
| |
| // Send window update when receive window size drops below this. |
| QuicByteCount WindowUpdateThreshold(); |
| |
| // Keep track of the last time we sent a BLOCKED frame. We should only send |
| // another when the number of bytes we have sent has changed. |
| QuicStreamOffset last_blocked_send_window_offset_; |
| |
| // Keep time of the last time a window update was sent. We use this |
| // as part of the receive window auto tuning. |
| QuicTime prev_window_update_time_; |
| }; |
| |
| } // namespace quic |
| |
| #endif // QUICHE_QUIC_CORE_QUIC_FLOW_CONTROLLER_H_ |