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| 1 // Copyright (c) 2012 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_DNS_DNS_SESSION_H_ | |
| 6 #define NET_DNS_DNS_SESSION_H_ | |
| 7 | |
| 8 #include <vector> | |
| 9 | |
| 10 #include "base/lazy_instance.h" | |
| 11 #include "base/memory/ref_counted.h" | |
| 12 #include "base/memory/scoped_ptr.h" | |
| 13 #include "base/memory/scoped_vector.h" | |
| 14 #include "base/metrics/bucket_ranges.h" | |
| 15 #include "base/time/time.h" | |
| 16 #include "net/base/net_export.h" | |
| 17 #include "net/base/rand_callback.h" | |
| 18 #include "net/dns/dns_config_service.h" | |
| 19 #include "net/dns/dns_socket_pool.h" | |
| 20 | |
| 21 namespace base { | |
| 22 class BucketRanges; | |
| 23 class SampleVector; | |
| 24 } | |
| 25 | |
| 26 namespace net { | |
| 27 | |
| 28 class ClientSocketFactory; | |
| 29 class DatagramClientSocket; | |
| 30 class NetLog; | |
| 31 class StreamSocket; | |
| 32 | |
| 33 // Session parameters and state shared between DNS transactions. | |
| 34 // Ref-counted so that DnsClient::Request can keep working in absence of | |
| 35 // DnsClient. A DnsSession must be recreated when DnsConfig changes. | |
| 36 class NET_EXPORT_PRIVATE DnsSession | |
| 37 : NON_EXPORTED_BASE(public base::RefCounted<DnsSession>) { | |
| 38 public: | |
| 39 typedef base::Callback<int()> RandCallback; | |
| 40 | |
| 41 class NET_EXPORT_PRIVATE SocketLease { | |
| 42 public: | |
| 43 SocketLease(scoped_refptr<DnsSession> session, | |
| 44 unsigned server_index, | |
| 45 scoped_ptr<DatagramClientSocket> socket); | |
| 46 ~SocketLease(); | |
| 47 | |
| 48 unsigned server_index() const { return server_index_; } | |
| 49 | |
| 50 DatagramClientSocket* socket() { return socket_.get(); } | |
| 51 | |
| 52 private: | |
| 53 scoped_refptr<DnsSession> session_; | |
| 54 unsigned server_index_; | |
| 55 scoped_ptr<DatagramClientSocket> socket_; | |
| 56 | |
| 57 DISALLOW_COPY_AND_ASSIGN(SocketLease); | |
| 58 }; | |
| 59 | |
| 60 DnsSession(const DnsConfig& config, | |
| 61 scoped_ptr<DnsSocketPool> socket_pool, | |
| 62 const RandIntCallback& rand_int_callback, | |
| 63 NetLog* net_log); | |
| 64 | |
| 65 const DnsConfig& config() const { return config_; } | |
| 66 NetLog* net_log() const { return net_log_; } | |
| 67 | |
| 68 // Return the next random query ID. | |
| 69 uint16 NextQueryId() const; | |
| 70 | |
| 71 // Return the index of the first configured server to use on first attempt. | |
| 72 unsigned NextFirstServerIndex(); | |
| 73 | |
| 74 // Start with |server_index| and find the index of the next known good server | |
| 75 // to use on this attempt. Returns |server_index| if this server has no | |
| 76 // recorded failures, or if there are no other servers that have not failed | |
| 77 // or have failed longer time ago. | |
| 78 unsigned NextGoodServerIndex(unsigned server_index); | |
| 79 | |
| 80 // Record that server failed to respond (due to SRV_FAIL or timeout). | |
| 81 void RecordServerFailure(unsigned server_index); | |
| 82 | |
| 83 // Record that server responded successfully. | |
| 84 void RecordServerSuccess(unsigned server_index); | |
| 85 | |
| 86 // Record how long it took to receive a response from the server. | |
| 87 void RecordRTT(unsigned server_index, base::TimeDelta rtt); | |
| 88 | |
| 89 // Record suspected loss of a packet for a specific server. | |
| 90 void RecordLostPacket(unsigned server_index, int attempt); | |
| 91 | |
| 92 // Record server stats before it is destroyed. | |
| 93 void RecordServerStats(); | |
| 94 | |
| 95 // Return the timeout for the next query. |attempt| counts from 0 and is used | |
| 96 // for exponential backoff. | |
| 97 base::TimeDelta NextTimeout(unsigned server_index, int attempt); | |
| 98 | |
| 99 // Allocate a socket, already connected to the server address. | |
| 100 // When the SocketLease is destroyed, the socket will be freed. | |
| 101 scoped_ptr<SocketLease> AllocateSocket(unsigned server_index, | |
| 102 const NetLog::Source& source); | |
| 103 | |
| 104 // Creates a StreamSocket from the factory for a transaction over TCP. These | |
| 105 // sockets are not pooled. | |
| 106 scoped_ptr<StreamSocket> CreateTCPSocket(unsigned server_index, | |
| 107 const NetLog::Source& source); | |
| 108 | |
| 109 private: | |
| 110 friend class base::RefCounted<DnsSession>; | |
| 111 ~DnsSession(); | |
| 112 | |
| 113 // Release a socket. | |
| 114 void FreeSocket(unsigned server_index, | |
| 115 scoped_ptr<DatagramClientSocket> socket); | |
| 116 | |
| 117 // Return the timeout using the TCP timeout method. | |
| 118 base::TimeDelta NextTimeoutFromJacobson(unsigned server_index, int attempt); | |
| 119 | |
| 120 // Compute the timeout using the histogram method. | |
| 121 base::TimeDelta NextTimeoutFromHistogram(unsigned server_index, int attempt); | |
| 122 | |
| 123 const DnsConfig config_; | |
| 124 scoped_ptr<DnsSocketPool> socket_pool_; | |
| 125 RandCallback rand_callback_; | |
| 126 NetLog* net_log_; | |
| 127 | |
| 128 // Current index into |config_.nameservers| to begin resolution with. | |
| 129 int server_index_; | |
| 130 | |
| 131 struct ServerStats; | |
| 132 | |
| 133 // Track runtime statistics of each DNS server. | |
| 134 ScopedVector<ServerStats> server_stats_; | |
| 135 | |
| 136 // Buckets shared for all |ServerStats::rtt_histogram|. | |
| 137 struct RttBuckets : public base::BucketRanges { | |
| 138 RttBuckets(); | |
| 139 }; | |
| 140 static base::LazyInstance<RttBuckets>::Leaky rtt_buckets_; | |
| 141 | |
| 142 DISALLOW_COPY_AND_ASSIGN(DnsSession); | |
| 143 }; | |
| 144 | |
| 145 } // namespace net | |
| 146 | |
| 147 #endif // NET_DNS_DNS_SESSION_H_ | |
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Chromium Code Reviews
Issue 992733002:
Remove //net (except for Android test stuff) and sdch (Closed)
Base URL: git@github.com:domokit/mojo.git@master