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 15namespace net { 16 17class BoundNetLog; 18class DnsResponse; 19class 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. 27class NET_EXPORT_PRIVATE DnsTransaction { 28 public: 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. 45class 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 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