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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/logging.h"
     11 #include "base/memory/scoped_ptr.h"
     12 #include "base/synchronization/lock.h"
     13 #include "net/quic/quic_alarm.h"
     14 #include "net/quic/quic_blocked_writer_interface.h"
     15 #include "net/quic/quic_packet_writer.h"
     16 #include "net/quic/test_tools/quic_test_writer.h"
     17 #include "net/tools/quic/quic_epoll_clock.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 net::test::QuicTestWriter {
     29  public:
     30   PacketDroppingTestWriter();
     31 
     32   virtual ~PacketDroppingTestWriter();
     33 
     34   void SetConnectionHelper(QuicEpollConnectionHelper* helper);
     35 
     36   // QuicPacketWriter methods:
     37   virtual WriteResult WritePacket(
     38       const char* buffer, size_t buf_len,
     39       const IPAddressNumber& self_address,
     40       const IPEndPoint& peer_address,
     41       QuicBlockedWriterInterface* blocked_writer) OVERRIDE;
     42 
     43   virtual bool IsWriteBlockedDataBuffered() const OVERRIDE;
     44 
     45   // Writes out any packet which should have been sent by now
     46   // to the contained writer and returns the time
     47   // for the next delayed packet to be written.
     48   QuicTime ReleaseOldPackets();
     49 
     50   QuicBlockedWriterInterface* blocked_writer() { return blocked_writer_; }
     51 
     52   // The percent of time a packet is simulated as being lost.
     53   void set_fake_packet_loss_percentage(int32 fake_packet_loss_percentage) {
     54     base::AutoLock locked(config_mutex_);
     55     fake_packet_loss_percentage_ = fake_packet_loss_percentage;
     56   }
     57 
     58   // The percent of time WritePacket will block and set WriteResult's status
     59   // to WRITE_STATUS_BLOCKED.
     60   void set_fake_blocked_socket_percentage(
     61       int32 fake_blocked_socket_percentage) {
     62     DCHECK(clock_);
     63     base::AutoLock locked(config_mutex_);
     64     fake_blocked_socket_percentage_  = fake_blocked_socket_percentage;
     65   }
     66 
     67   // The percent of time a packet is simulated as being reordered.
     68   void set_fake_reorder_percentage(int32 fake_packet_reorder_percentage) {
     69     DCHECK(clock_);
     70     base::AutoLock locked(config_mutex_);
     71     DCHECK(!fake_packet_delay_.IsZero());
     72     fake_packet_reorder_percentage_ = fake_packet_reorder_percentage;
     73   }
     74 
     75   // The percent of time WritePacket will block and set WriteResult's status
     76   // to WRITE_STATUS_BLOCKED.
     77   void set_fake_packet_delay(QuicTime::Delta fake_packet_delay) {
     78     DCHECK(clock_);
     79     base::AutoLock locked(config_mutex_);
     80     fake_packet_delay_  = fake_packet_delay;
     81   }
     82 
     83   // The maximum bandwidth and buffer size of the connection.  When these are
     84   // set, packets will be delayed until a connection with that bandwidth would
     85   // transmit it.  Once the |buffer_size| is reached, all new packets are
     86   // dropped.
     87   void set_max_bandwidth_and_buffer_size(QuicBandwidth fake_bandwidth,
     88                                          QuicByteCount buffer_size) {
     89     DCHECK(clock_);
     90     base::AutoLock locked(config_mutex_);
     91     fake_bandwidth_ = fake_bandwidth;
     92     buffer_size_ = buffer_size;
     93   }
     94 
     95   void set_seed(uint64 seed) {
     96     simple_random_.set_seed(seed);
     97   }
     98 
     99  private:
    100   // Writes out the next packet to the contained writer and returns the time
    101   // for the next delayed packet to be written.
    102   QuicTime ReleaseNextPacket();
    103 
    104   // A single packet which will be sent at the supplied send_time.
    105   class DelayedWrite {
    106    public:
    107     DelayedWrite(const char* buffer,
    108                  size_t buf_len,
    109                  const IPAddressNumber& self_address,
    110                  const IPEndPoint& peer_address,
    111                  QuicTime send_time);
    112     ~DelayedWrite();
    113 
    114     string buffer;
    115     const IPAddressNumber self_address;
    116     const IPEndPoint peer_address;
    117     QuicTime send_time;
    118   };
    119 
    120   typedef std::list<DelayedWrite> DelayedPacketList;
    121 
    122   const QuicClock* clock_;
    123   scoped_ptr<QuicAlarm> write_unblocked_alarm_;
    124   scoped_ptr<QuicAlarm> delay_alarm_;
    125   QuicBlockedWriterInterface* blocked_writer_;
    126   SimpleRandom simple_random_;
    127   // Stored packets delayed by fake packet delay or bandwidth restrictions.
    128   DelayedPacketList delayed_packets_;
    129   QuicByteCount cur_buffer_size_;
    130 
    131   base::Lock config_mutex_;
    132   int32 fake_packet_loss_percentage_;
    133   int32 fake_blocked_socket_percentage_;
    134   int32 fake_packet_reorder_percentage_;
    135   QuicTime::Delta fake_packet_delay_;
    136   QuicBandwidth fake_bandwidth_;
    137   QuicByteCount buffer_size_;
    138 
    139   DISALLOW_COPY_AND_ASSIGN(PacketDroppingTestWriter);
    140 };
    141 
    142 }  // namespace test
    143 }  // namespace tools
    144 }  // namespace net
    145 
    146 #endif  // NET_TOOLS_QUIC_TEST_TOOLS_PACKET_DROPPING_TEST_WRITER_H_
    147