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      1 // Copyright 2013 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_TOOLS_QUIC_TEST_TOOLS_PACKET_DROPPING_TEST_WRITER_H_
      6 #define NET_TOOLS_QUIC_TEST_TOOLS_PACKET_DROPPING_TEST_WRITER_H_
      7 
      8 #include <list>
      9 
     10 #include "base/basictypes.h"
     11 #include "base/logging.h"
     12 #include "base/memory/scoped_ptr.h"
     13 #include "base/synchronization/lock.h"
     14 #include "net/quic/quic_alarm.h"
     15 #include "net/quic/test_tools/quic_test_utils.h"
     16 #include "net/tools/quic/quic_epoll_clock.h"
     17 #include "net/tools/quic/quic_packet_writer_wrapper.h"
     18 #include "net/tools/quic/test_tools/quic_test_client.h"
     19 #include "net/tools/quic/test_tools/quic_test_utils.h"
     20 
     21 namespace net {
     22 namespace tools {
     23 namespace test {
     24 
     25 // Simulates a connection that drops packets a configured percentage of the time
     26 // and has a blocked socket a configured percentage of the time.  Also provides
     27 // the options to delay packets and reorder packets if delay is enabled.
     28 class PacketDroppingTestWriter : public QuicPacketWriterWrapper {
     29  public:
     30   class Delegate {
     31    public:
     32     virtual ~Delegate() {}
     33     virtual void OnPacketSent(WriteResult result) = 0;
     34     virtual void OnCanWrite() = 0;
     35   };
     36 
     37   PacketDroppingTestWriter();
     38 
     39   virtual ~PacketDroppingTestWriter();
     40 
     41   // Must be called before blocking, reordering or delaying (loss is OK). May be
     42   // called after connecting if the helper is not available before.
     43   // |on_can_write| will be triggered when fake-unblocking; ownership will be
     44   // assumed.
     45   void Initialize(QuicEpollConnectionHelper* helper, Delegate* on_can_write);
     46 
     47   // QuicPacketWriter methods:
     48   virtual WriteResult WritePacket(
     49       const char* buffer,
     50       size_t buf_len,
     51       const IPAddressNumber& self_address,
     52       const IPEndPoint& peer_address) OVERRIDE;
     53 
     54   virtual bool IsWriteBlocked() const OVERRIDE;
     55 
     56   virtual void SetWritable() OVERRIDE;
     57 
     58   // Writes out any packet which should have been sent by now
     59   // to the contained writer and returns the time
     60   // for the next delayed packet to be written.
     61   QuicTime ReleaseOldPackets();
     62 
     63   void OnCanWrite();
     64 
     65   // The percent of time a packet is simulated as being lost.
     66   void set_fake_packet_loss_percentage(int32 fake_packet_loss_percentage) {
     67     base::AutoLock locked(config_mutex_);
     68     fake_packet_loss_percentage_ = fake_packet_loss_percentage;
     69   }
     70 
     71   // The percent of time WritePacket will block and set WriteResult's status
     72   // to WRITE_STATUS_BLOCKED.
     73   void set_fake_blocked_socket_percentage(
     74       int32 fake_blocked_socket_percentage) {
     75     DCHECK(clock_);
     76     base::AutoLock locked(config_mutex_);
     77     fake_blocked_socket_percentage_  = fake_blocked_socket_percentage;
     78   }
     79 
     80   // The percent of time a packet is simulated as being reordered.
     81   void set_fake_reorder_percentage(int32 fake_packet_reorder_percentage) {
     82     DCHECK(clock_);
     83     base::AutoLock locked(config_mutex_);
     84     DCHECK(!fake_packet_delay_.IsZero());
     85     fake_packet_reorder_percentage_ = fake_packet_reorder_percentage;
     86   }
     87 
     88   // The percent of time WritePacket will block and set WriteResult's status
     89   // to WRITE_STATUS_BLOCKED.
     90   void set_fake_packet_delay(QuicTime::Delta fake_packet_delay) {
     91     DCHECK(clock_);
     92     base::AutoLock locked(config_mutex_);
     93     fake_packet_delay_  = fake_packet_delay;
     94   }
     95 
     96   // The maximum bandwidth and buffer size of the connection.  When these are
     97   // set, packets will be delayed until a connection with that bandwidth would
     98   // transmit it.  Once the |buffer_size| is reached, all new packets are
     99   // dropped.
    100   void set_max_bandwidth_and_buffer_size(QuicBandwidth fake_bandwidth,
    101                                          QuicByteCount buffer_size) {
    102     DCHECK(clock_);
    103     base::AutoLock locked(config_mutex_);
    104     fake_bandwidth_ = fake_bandwidth;
    105     buffer_size_ = buffer_size;
    106   }
    107 
    108   void set_seed(uint64 seed) {
    109     simple_random_.set_seed(seed);
    110   }
    111 
    112  private:
    113   // Writes out the next packet to the contained writer and returns the time
    114   // for the next delayed packet to be written.
    115   QuicTime ReleaseNextPacket();
    116 
    117   // A single packet which will be sent at the supplied send_time.
    118   struct DelayedWrite {
    119    public:
    120     DelayedWrite(const char* buffer,
    121                  size_t buf_len,
    122                  const IPAddressNumber& self_address,
    123                  const IPEndPoint& peer_address,
    124                  QuicTime send_time);
    125     ~DelayedWrite();
    126 
    127     string buffer;
    128     const IPAddressNumber self_address;
    129     const IPEndPoint peer_address;
    130     QuicTime send_time;
    131   };
    132 
    133   typedef std::list<DelayedWrite> DelayedPacketList;
    134 
    135   const QuicClock* clock_;
    136   scoped_ptr<QuicAlarm> write_unblocked_alarm_;
    137   scoped_ptr<QuicAlarm> delay_alarm_;
    138   scoped_ptr<Delegate> on_can_write_;
    139   net::test::SimpleRandom simple_random_;
    140   // Stored packets delayed by fake packet delay or bandwidth restrictions.
    141   DelayedPacketList delayed_packets_;
    142   QuicByteCount cur_buffer_size_;
    143 
    144   base::Lock config_mutex_;
    145   int32 fake_packet_loss_percentage_;
    146   int32 fake_blocked_socket_percentage_;
    147   int32 fake_packet_reorder_percentage_;
    148   QuicTime::Delta fake_packet_delay_;
    149   QuicBandwidth fake_bandwidth_;
    150   QuicByteCount buffer_size_;
    151 
    152   DISALLOW_COPY_AND_ASSIGN(PacketDroppingTestWriter);
    153 };
    154 
    155 }  // namespace test
    156 }  // namespace tools
    157 }  // namespace net
    158 
    159 #endif  // NET_TOOLS_QUIC_TEST_TOOLS_PACKET_DROPPING_TEST_WRITER_H_
    160