Home | History | Annotate | Download | only in dns 
      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 NET_DNS_MDNS_CLIENT_IMPL_H_
      6 #define NET_DNS_MDNS_CLIENT_IMPL_H_
      7 
      8 #include <map>
      9 #include <string>
     10 #include <utility>
     11 #include <vector>
     12 
     13 #include "base/cancelable_callback.h"
     14 #include "base/memory/scoped_vector.h"
     15 #include "base/observer_list.h"
     16 #include "net/base/io_buffer.h"
     17 #include "net/base/ip_endpoint.h"
     18 #include "net/dns/mdns_cache.h"
     19 #include "net/dns/mdns_client.h"
     20 #include "net/udp/datagram_server_socket.h"
     21 #include "net/udp/udp_server_socket.h"
     22 #include "net/udp/udp_socket.h"
     23 
     24 namespace net {
     25 
     26 class MDnsSocketFactoryImpl : public MDnsSocketFactory {
     27  public:
     28   MDnsSocketFactoryImpl() {};
     29   virtual ~MDnsSocketFactoryImpl() {};
     30 
     31   virtual void CreateSockets(
     32       ScopedVector<DatagramServerSocket>* sockets) OVERRIDE;
     33 
     34  private:
     35   DISALLOW_COPY_AND_ASSIGN(MDnsSocketFactoryImpl);
     36 };
     37 
     38 // A connection to the network for multicast DNS clients. It reads data into
     39 // DnsResponse objects and alerts the delegate that a packet has been received.
     40 class NET_EXPORT_PRIVATE MDnsConnection {
     41  public:
     42   class Delegate {
     43    public:
     44     // Handle an mDNS packet buffered in |response| with a size of |bytes_read|.
     45     virtual void HandlePacket(DnsResponse* response, int bytes_read) = 0;
     46     virtual void OnConnectionError(int error) = 0;
     47     virtual ~Delegate() {}
     48   };
     49 
     50   explicit MDnsConnection(MDnsConnection::Delegate* delegate);
     51   virtual ~MDnsConnection();
     52 
     53   // Both methods return true if at least one of the socket handlers succeeded.
     54   bool Init(MDnsSocketFactory* socket_factory);
     55   bool Send(IOBuffer* buffer, unsigned size);
     56 
     57  private:
     58   class SocketHandler {
     59    public:
     60     SocketHandler(scoped_ptr<DatagramServerSocket> socket,
     61                   MDnsConnection* connection);
     62     ~SocketHandler();
     63 
     64     int Start();
     65     int Send(IOBuffer* buffer, unsigned size);
     66 
     67    private:
     68     int DoLoop(int rv);
     69     void OnDatagramReceived(int rv);
     70 
     71     // Callback for when sending a query has finished.
     72     void SendDone(int rv);
     73 
     74     scoped_ptr<DatagramServerSocket> socket_;
     75     MDnsConnection* connection_;
     76     IPEndPoint recv_addr_;
     77     DnsResponse response_;
     78     IPEndPoint multicast_addr_;
     79 
     80     DISALLOW_COPY_AND_ASSIGN(SocketHandler);
     81   };
     82 
     83   // Callback for handling a datagram being received on either ipv4 or ipv6.
     84   void OnDatagramReceived(DnsResponse* response,
     85                           const IPEndPoint& recv_addr,
     86                           int bytes_read);
     87 
     88   void OnError(SocketHandler* loop, int error);
     89 
     90   // Only socket handlers which successfully bound and started are kept.
     91   ScopedVector<SocketHandler> socket_handlers_;
     92 
     93   Delegate* delegate_;
     94 
     95   DISALLOW_COPY_AND_ASSIGN(MDnsConnection);
     96 };
     97 
     98 class MDnsListenerImpl;
     99 
    100 class NET_EXPORT_PRIVATE MDnsClientImpl : public MDnsClient {
    101  public:
    102   // The core object exists while the MDnsClient is listening, and is deleted
    103   // whenever the number of listeners reaches zero. The deletion happens
    104   // asychronously, so destroying the last listener does not immediately
    105   // invalidate the core.
    106   class Core : public base::SupportsWeakPtr<Core>, MDnsConnection::Delegate {
    107    public:
    108     explicit Core(MDnsClientImpl* client);
    109     virtual ~Core();
    110 
    111     // Initialize the core. Returns true on success.
    112     bool Init(MDnsSocketFactory* socket_factory);
    113 
    114     // Send a query with a specific rrtype and name. Returns true on success.
    115     bool SendQuery(uint16 rrtype, std::string name);
    116 
    117     // Add/remove a listener to the list of listeners.
    118     void AddListener(MDnsListenerImpl* listener);
    119     void RemoveListener(MDnsListenerImpl* listener);
    120 
    121     // Query the cache for records of a specific type and name.
    122     void QueryCache(uint16 rrtype, const std::string& name,
    123                     std::vector<const RecordParsed*>* records) const;
    124 
    125     // Parse the response and alert relevant listeners.
    126     virtual void HandlePacket(DnsResponse* response, int bytes_read) OVERRIDE;
    127 
    128     virtual void OnConnectionError(int error) OVERRIDE;
    129 
    130    private:
    131     typedef std::pair<std::string, uint16> ListenerKey;
    132     typedef std::map<ListenerKey, ObserverList<MDnsListenerImpl>* >
    133     ListenerMap;
    134 
    135     // Alert listeners of an update to the cache.
    136     void AlertListeners(MDnsListener::UpdateType update_type,
    137                         const ListenerKey& key, const RecordParsed* record);
    138 
    139     // Schedule a cache cleanup to a specific time, cancelling other cleanups.
    140     void ScheduleCleanup(base::Time cleanup);
    141 
    142     // Clean up the cache and schedule a new cleanup.
    143     void DoCleanup();
    144 
    145     // Callback for when a record is removed from the cache.
    146     void OnRecordRemoved(const RecordParsed* record);
    147 
    148     void NotifyNsecRecord(const RecordParsed* record);
    149 
    150     // Delete and erase the observer list for |key|. Only deletes the observer
    151     // list if is empty.
    152     void CleanupObserverList(const ListenerKey& key);
    153 
    154     ListenerMap listeners_;
    155 
    156     MDnsClientImpl* client_;
    157     MDnsCache cache_;
    158 
    159     base::CancelableCallback<void()> cleanup_callback_;
    160     base::Time scheduled_cleanup_;
    161 
    162     scoped_ptr<MDnsConnection> connection_;
    163 
    164     DISALLOW_COPY_AND_ASSIGN(Core);
    165   };
    166 
    167   MDnsClientImpl();
    168   virtual ~MDnsClientImpl();
    169 
    170   // MDnsClient implementation:
    171   virtual scoped_ptr<MDnsListener> CreateListener(
    172       uint16 rrtype,
    173       const std::string& name,
    174       MDnsListener::Delegate* delegate) OVERRIDE;
    175 
    176   virtual scoped_ptr<MDnsTransaction> CreateTransaction(
    177       uint16 rrtype,
    178       const std::string& name,
    179       int flags,
    180       const MDnsTransaction::ResultCallback& callback) OVERRIDE;
    181 
    182   virtual bool StartListening(MDnsSocketFactory* socket_factory) OVERRIDE;
    183   virtual void StopListening() OVERRIDE;
    184   virtual bool IsListening() const OVERRIDE;
    185 
    186   Core* core() { return core_.get(); }
    187 
    188  private:
    189   scoped_ptr<Core> core_;
    190 
    191   DISALLOW_COPY_AND_ASSIGN(MDnsClientImpl);
    192 };
    193 
    194 class MDnsListenerImpl : public MDnsListener,
    195                          public base::SupportsWeakPtr<MDnsListenerImpl> {
    196  public:
    197   MDnsListenerImpl(uint16 rrtype,
    198                    const std::string& name,
    199                    MDnsListener::Delegate* delegate,
    200                    MDnsClientImpl* client);
    201 
    202   virtual ~MDnsListenerImpl();
    203 
    204   // MDnsListener implementation:
    205   virtual bool Start() OVERRIDE;
    206 
    207   virtual const std::string& GetName() const OVERRIDE;
    208 
    209   virtual uint16 GetType() const OVERRIDE;
    210 
    211   MDnsListener::Delegate* delegate() { return delegate_; }
    212 
    213   // Alert the delegate of a record update.
    214   void AlertDelegate(MDnsListener::UpdateType update_type,
    215                      const RecordParsed* record_parsed);
    216 
    217   // Alert the delegate of the existence of an Nsec record.
    218   void AlertNsecRecord();
    219 
    220  private:
    221   uint16 rrtype_;
    222   std::string name_;
    223   MDnsClientImpl* client_;
    224   MDnsListener::Delegate* delegate_;
    225 
    226   bool started_;
    227   DISALLOW_COPY_AND_ASSIGN(MDnsListenerImpl);
    228 };
    229 
    230 class MDnsTransactionImpl : public base::SupportsWeakPtr<MDnsTransactionImpl>,
    231                             public MDnsTransaction,
    232                             public MDnsListener::Delegate {
    233  public:
    234   MDnsTransactionImpl(uint16 rrtype,
    235                       const std::string& name,
    236                       int flags,
    237                       const MDnsTransaction::ResultCallback& callback,
    238                       MDnsClientImpl* client);
    239   virtual ~MDnsTransactionImpl();
    240 
    241   // MDnsTransaction implementation:
    242   virtual bool Start() OVERRIDE;
    243 
    244   virtual const std::string& GetName() const OVERRIDE;
    245   virtual uint16 GetType() const OVERRIDE;
    246 
    247   // MDnsListener::Delegate implementation:
    248   virtual void OnRecordUpdate(MDnsListener::UpdateType update,
    249                               const RecordParsed* record) OVERRIDE;
    250   virtual void OnNsecRecord(const std::string& name, unsigned type) OVERRIDE;
    251 
    252   virtual void OnCachePurged() OVERRIDE;
    253 
    254  private:
    255   bool is_active() { return !callback_.is_null(); }
    256 
    257   void Reset();
    258 
    259   // Trigger the callback and reset all related variables.
    260   void TriggerCallback(MDnsTransaction::Result result,
    261                        const RecordParsed* record);
    262 
    263   // Internal callback for when a cache record is found.
    264   void CacheRecordFound(const RecordParsed* record);
    265 
    266   // Signal the transactionis over and release all related resources.
    267   void SignalTransactionOver();
    268 
    269   // Reads records from the cache and calls the callback for every
    270   // record read.
    271   void ServeRecordsFromCache();
    272 
    273   // Send a query to the network and set up a timeout to time out the
    274   // transaction. Returns false if it fails to start listening on the network
    275   // or if it fails to send a query.
    276   bool QueryAndListen();
    277 
    278   uint16 rrtype_;
    279   std::string name_;
    280   MDnsTransaction::ResultCallback callback_;
    281 
    282   scoped_ptr<MDnsListener> listener_;
    283   base::CancelableCallback<void()> timeout_;
    284 
    285   MDnsClientImpl* client_;
    286 
    287   bool started_;
    288   int flags_;
    289 
    290   DISALLOW_COPY_AND_ASSIGN(MDnsTransactionImpl);
    291 };
    292 
    293 }  // namespace net
    294 #endif  // NET_DNS_MDNS_CLIENT_IMPL_H_
    295