net/quic/quic_flow_controller.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef NET_QUIC_QUIC_FLOW_CONTROLLER_H_
   6 #define NET_QUIC_QUIC_FLOW_CONTROLLER_H_
   7
   8 #include "base/basictypes.h"
   9 #include "net/base/net_export.h"
  10 #include "net/quic/quic_protocol.h"
  11
  12 namespace net {
  13
  14 namespace test {
  15 class QuicFlowControllerPeer;
  16 }  // namespace test
  17
  18 class QuicConnection;
  19
  20 const QuicStreamId kConnectionLevelId = 0;
  21
  22 // QuicFlowController allows a QUIC stream or connection to perform flow
  23 // control. The stream/connection owns a QuicFlowController which keeps track of
  24 // bytes sent/received, can tell the owner if it is flow control blocked, and
  25 // can send WINDOW_UPDATE or BLOCKED frames when needed.
  26 class NET_EXPORT_PRIVATE QuicFlowController {
  27  public:
  28   QuicFlowController(QuicConnection* connection,
  29                      QuicStreamId id,
  30                      bool is_server,
  31                      uint64 send_window_offset,
  32                      uint64 receive_window_offset,
  33                      uint64 max_receive_window);
  34   ~QuicFlowController() {}
  35
  36   // Called when we see a new highest received byte offset from the peer, either
  37   // via a data frame or a RST.
  38   // Returns true if this call changes highest_received_byte_offset_, and false
  39   // in the case where |new_offset| is <= highest_received_byte_offset_.
  40   bool UpdateHighestReceivedOffset(uint64 new_offset);
  41
  42   // Called when bytes received from the peer are consumed locally. This may
  43   // trigger the sending of a WINDOW_UPDATE frame using |connection|.
  44   void AddBytesConsumed(uint64 bytes_consumed);
  45
  46   // Called when bytes are sent to the peer.
  47   void AddBytesSent(uint64 bytes_sent);
  48
  49   // Set a new send window offset.
  50   // Returns true if this changes send_window_offset_, and false in the case
  51   // where |new_send_window| is <= send_window_offset_.
  52   bool UpdateSendWindowOffset(uint64 new_send_window_offset);
  53
  54   // Returns the current available send window.
  55   uint64 SendWindowSize() const;
  56
  57   // Send a BLOCKED frame if appropriate.
  58   void MaybeSendBlocked();
  59
  60   // Disable flow control.
  61   void Disable();
  62
  63   // Returns true if flow control is enabled.
  64   bool IsEnabled() const;
  65
  66   // Returns true if flow control send limits have been reached.
  67   bool IsBlocked() const;
  68
  69   // Returns true if flow control receive limits have been violated by the peer.
  70   bool FlowControlViolation();
  71
  72   uint64 bytes_consumed() const { return bytes_consumed_; }
  73
  74   uint64 highest_received_byte_offset() const {
  75     return highest_received_byte_offset_;
  76   }
  77
  78  private:
  79   friend class test::QuicFlowControllerPeer;
  80
  81   // Send a WINDOW_UPDATE frame if appropriate.
  82   void MaybeSendWindowUpdate();
  83
  84   // The parent connection, used to send connection close on flow control
  85   // violation, and WINDOW_UPDATE and BLOCKED frames when appropriate.
  86   // Not owned.
  87   QuicConnection* connection_;
  88
  89   // ID of stream this flow controller belongs to. This can be 0 if this is a
  90   // connection level flow controller.
  91   QuicStreamId id_;
  92
  93   // True if flow control is enabled.
  94   bool is_enabled_;
  95
  96   // True if this is owned by a server.
  97   bool is_server_;
  98
  99   // Track number of bytes received from the peer, which have been consumed
 100   // locally.
 101   uint64 bytes_consumed_;
 102
 103   // The highest byte offset we have seen from the peer. This could be the
 104   // highest offset in a data frame, or a final value in a RST.
 105   uint64 highest_received_byte_offset_;
 106
 107   // Tracks number of bytes sent to the peer.
 108   uint64 bytes_sent_;
 109
 110   // The absolute offset in the outgoing byte stream. If this offset is reached
 111   // then we become flow control blocked until we receive a WINDOW_UPDATE.
 112   uint64 send_window_offset_;
 113
 114   // The absolute offset in the incoming byte stream. The peer should never send
 115   // us bytes which are beyond this offset.
 116   uint64 receive_window_offset_;
 117
 118   // Largest size the receive window can grow to.
 119   uint64 max_receive_window_;
 120
 121   // Keep track of the last time we sent a BLOCKED frame. We should only send
 122   // another when the number of bytes we have sent has changed.
 123   uint64 last_blocked_send_window_offset_;
 124
 125   DISALLOW_COPY_AND_ASSIGN(QuicFlowController);
 126 };
 127
 128 }  // namespace net
 129
 130 #endif  // NET_QUIC_QUIC_FLOW_CONTROLLER_H_