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 CHROME_BROWSER_NET_DNS_PROBE_RUNNER_H_ 6 #define CHROME_BROWSER_NET_DNS_PROBE_RUNNER_H_ 7 8 #include "base/basictypes.h" 9 #include "base/bind.h" 10 #include "base/memory/scoped_ptr.h" 11 #include "base/memory/weak_ptr.h" 12 13 namespace net { 14 class DnsClient; 15 class DnsResponse; 16 class DnsTransaction; 17 } 18 19 namespace chrome_browser_net { 20 21 // Runs DNS probes using a single DnsClient and evaluates the responses. 22 // (Currently requests A records for google.com and expects at least one IP 23 // address in the response.) 24 // Used by DnsProbeService to probe the system and public DNS configurations. 25 class DnsProbeRunner { 26 public: 27 static const char* kKnownGoodHostname; 28 29 // Used in histograms; add new entries at the bottom, and don't remove any. 30 enum Result { 31 UNKNOWN, 32 CORRECT, // Response contains at least one A record. 33 INCORRECT, // Response claimed success but included no A records. 34 FAILING, // Response included an error or was malformed. 35 UNREACHABLE // No response received (timeout, network unreachable, etc.). 36 }; 37 38 DnsProbeRunner(); 39 ~DnsProbeRunner(); 40 41 // Sets the DnsClient that will be used for DNS probes sent by this runner. 42 // Must be called before RunProbe; can be called repeatedly, including during 43 // a probe. It will not affect an in-flight probe, if one is running. 44 void SetClient(scoped_ptr<net::DnsClient> client); 45 46 // Starts a probe using the client specified with SetClient, which must have 47 // been called before RunProbe. |callback| will be called asynchronously 48 // when the result is ready, even if it is ready synchronously. Must not 49 // be called again until the callback is called, but may be called during the 50 // callback. 51 void RunProbe(const base::Closure& callback); 52 53 // Returns true if a probe is running. Guaranteed to return true after 54 // RunProbe returns, and false during and after the callback. 55 bool IsRunning() const; 56 57 // Returns the result of the last probe. result()58 Result result() const { return result_; } 59 60 private: 61 void OnTransactionComplete(net::DnsTransaction* transaction, 62 int net_error, 63 const net::DnsResponse* response); 64 void CallCallback(); 65 66 scoped_ptr<net::DnsClient> client_; 67 68 // The callback passed to |RunProbe|. Cleared right before calling the 69 // callback. 70 base::Closure callback_; 71 72 // The transaction started in |RunProbe| for the DNS probe. Reset once the 73 // results have been examined. 74 scoped_ptr<net::DnsTransaction> transaction_; 75 76 Result result_; 77 78 base::WeakPtrFactory<DnsProbeRunner> weak_factory_; 79 80 DISALLOW_COPY_AND_ASSIGN(DnsProbeRunner); 81 }; 82 83 } // namespace chrome_browser_net 84 85 #endif // CHROME_BROWSER_NET_DNS_PROBE_RUNNER_H_ 86