1 // 2 // Copyright (C) 2011 The Android Open Source Project 3 // 4 // Licensed under the Apache License, Version 2.0 (the "License"); 5 // you may not use this file except in compliance with the License. 6 // You may obtain a copy of the License at 7 // 8 // http://www.apache.org/licenses/LICENSE-2.0 9 // 10 // Unless required by applicable law or agreed to in writing, software 11 // distributed under the License is distributed on an "AS IS" BASIS, 12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 // See the License for the specific language governing permissions and 14 // limitations under the License. 15 // 16 17 #ifndef SHILL_DNS_CLIENT_H_ 18 #define SHILL_DNS_CLIENT_H_ 19 20 #include <memory> 21 #include <string> 22 #include <vector> 23 24 #include <base/callback.h> 25 #include <base/cancelable_callback.h> 26 #include <base/memory/weak_ptr.h> 27 #include <gtest/gtest_prod.h> // for FRIEND_TEST 28 29 #include "shill/error.h" 30 #include "shill/event_dispatcher.h" 31 #include "shill/net/ip_address.h" 32 #include "shill/refptr_types.h" 33 34 struct hostent; 35 36 namespace shill { 37 38 class Ares; 39 class Time; 40 struct DNSClientState; 41 42 // Implements a DNS resolution client that can run asynchronously. 43 class DNSClient { 44 public: 45 typedef base::Callback<void(const Error&, const IPAddress&)> ClientCallback; 46 47 static const char kErrorNoData[]; 48 static const char kErrorFormErr[]; 49 static const char kErrorServerFail[]; 50 static const char kErrorNotFound[]; 51 static const char kErrorNotImp[]; 52 static const char kErrorRefused[]; 53 static const char kErrorBadQuery[]; 54 static const char kErrorNetRefused[]; 55 static const char kErrorTimedOut[]; 56 static const char kErrorUnknown[]; 57 58 DNSClient(IPAddress::Family family, 59 const std::string& interface_name, 60 const std::vector<std::string>& dns_servers, 61 int timeout_ms, 62 EventDispatcher* dispatcher, 63 const ClientCallback& callback); 64 virtual ~DNSClient(); 65 66 // Returns true if the DNS client started successfully, false otherwise. 67 // If successful, the callback will be called with the result of the 68 // request. If Start() fails and returns false, the callback will not 69 // be called, but the error that caused the failure will be returned in 70 // |error|. 71 virtual bool Start(const std::string& hostname, Error* error); 72 73 // Aborts any running DNS client transaction. This will cancel any callback 74 // invocation. 75 virtual void Stop(); 76 77 virtual bool IsActive() const; 78 79 std::string interface_name() { return interface_name_; } 80 81 private: 82 friend class DNSClientTest; 83 84 void HandleCompletion(); 85 void HandleDNSRead(int fd); 86 void HandleDNSWrite(int fd); 87 void HandleTimeout(); 88 void ReceiveDNSReply(int status, struct hostent* hostent); 89 static void ReceiveDNSReplyCB(void* arg, int status, int timeouts, 90 struct hostent* hostent); 91 bool RefreshHandles(); 92 93 static const int kDefaultDNSPort; 94 95 Error error_; 96 IPAddress address_; 97 std::string interface_name_; 98 std::vector<std::string> dns_servers_; 99 EventDispatcher* dispatcher_; 100 ClientCallback callback_; 101 int timeout_ms_; 102 bool running_; 103 std::unique_ptr<DNSClientState> resolver_state_; 104 base::CancelableClosure timeout_closure_; 105 base::WeakPtrFactory<DNSClient> weak_ptr_factory_; 106 Ares* ares_; 107 Time* time_; 108 109 DISALLOW_COPY_AND_ASSIGN(DNSClient); 110 }; 111 112 } // namespace shill 113 114 #endif // SHILL_DNS_CLIENT_H_ 115
