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_TRANSACTION_H_ 6 #define NET_DNS_DNS_TRANSACTION_H_ 7 8 #include <string> 9 10 #include "base/basictypes.h" 11 #include "base/callback_forward.h" 12 #include "base/memory/scoped_ptr.h" 13 #include "net/base/net_export.h" 14 15 namespace net { 16 17 class BoundNetLog; 18 class DnsResponse; 19 class DnsSession; 20 21 // DnsTransaction implements a stub DNS resolver as defined in RFC 1034. 22 // The DnsTransaction takes care of retransmissions, name server fallback (or 23 // round-robin), suffix search, and simple response validation ("does it match 24 // the query") to fight poisoning. 25 // 26 // Destroying DnsTransaction cancels the underlying network effort. 27 class NET_EXPORT_PRIVATE DnsTransaction { 28 public: ~DnsTransaction()29 virtual ~DnsTransaction() {} 30 31 // Returns the original |hostname|. 32 virtual const std::string& GetHostname() const = 0; 33 34 // Returns the |qtype|. 35 virtual uint16 GetType() const = 0; 36 37 // Starts the transaction. Always completes asynchronously. 38 virtual void Start() = 0; 39 }; 40 41 // Creates DnsTransaction which performs asynchronous DNS search. 42 // It does NOT perform caching, aggregation or prioritization of transactions. 43 // 44 // Destroying the factory does NOT affect any already created DnsTransactions. 45 class NET_EXPORT_PRIVATE DnsTransactionFactory { 46 public: 47 // Called with the response or NULL if no matching response was received. 48 // Note that the |GetDottedName()| of the response may be different than the 49 // original |hostname| as a result of suffix search. 50 typedef base::Callback<void(DnsTransaction* transaction, 51 int neterror, 52 const DnsResponse* response)> CallbackType; 53 ~DnsTransactionFactory()54 virtual ~DnsTransactionFactory() {} 55 56 // Creates DnsTransaction for the given |hostname| and |qtype| (assuming 57 // QCLASS is IN). |hostname| should be in the dotted form. A dot at the end 58 // implies the domain name is fully-qualified and will be exempt from suffix 59 // search. |hostname| should not be an IP literal. 60 // 61 // The transaction will run |callback| upon asynchronous completion. 62 // The |net_log| is used as the parent log. 63 virtual scoped_ptr<DnsTransaction> CreateTransaction( 64 const std::string& hostname, 65 uint16 qtype, 66 const CallbackType& callback, 67 const BoundNetLog& net_log) WARN_UNUSED_RESULT = 0; 68 69 // Creates a DnsTransactionFactory which creates DnsTransactionImpl using the 70 // |session|. 71 static scoped_ptr<DnsTransactionFactory> CreateFactory( 72 DnsSession* session) WARN_UNUSED_RESULT; 73 }; 74 75 } // namespace net 76 77 #endif // NET_DNS_DNS_TRANSACTION_H_ 78 79