Multicast DNS implementation (initial)

net/dns/mdns_client_impl.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_DNS_MDNS_CLIENT_IMPL_H_
 #define NET_DNS_MDNS_CLIENT_IMPL_H_
 
 #include <map>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "base/cancelable_callback.h"
 #include "base/observer_list.h"
 #include "net/base/io_buffer.h"
 #include "net/base/ip_endpoint.h"
 #include "net/dns/mdns_cache.h"
 #include "net/dns/mdns_client.h"
 #include "net/udp/datagram_server_socket.h"
 #include "net/udp/udp_server_socket.h"
 #include "net/udp/udp_socket.h"
 
 
 namespace net {
 
 class MDnsListenerImpl;
 
-// This class represents a connection to the network for multicast DNS clients.
-// It reads data into DNSResponse objects and alerts the delegate that a packet
-// has been received.
+// A connection to the network for multicast DNS clients. It reads data into
+// DnsResponse objects and alerts the delegate that a packet has been received.
 class MDnsConnection {
  public:
   class Delegate {
    public:
     // Handle an mDNS packet buffered in |response| with a size of |bytes_read|.
     virtual void HandlePacket(DnsResponse* response, int bytes_read) = 0;
+    virtual void OnConnectionError(int error) = 0;
     virtual ~Delegate() {}
   };
 
   // Start the connection. Will begin alerting the delegate of packets.
-  virtual bool Init() = 0;
+  // Returns a net error code.
+  virtual int Init() = 0;
 
-  // Send a packet on both ipv4 and ipv6.
-  virtual bool Send(IOBuffer* buffer, unsigned size) = 0;
+  // Send a packet on both ipv4 and ipv6. Returns a net error code.
+  virtual int Send(IOBuffer* buffer, unsigned size) = 0;
   virtual ~MDnsConnection() {}
 };
 
 class MDnsConnectionFactory {
  public:
   virtual scoped_ptr<MDnsConnection> CreateConnection(
       MDnsConnection::Delegate* delegate) = 0;
 
   virtual ~MDnsConnectionFactory() {}
 };
@@ skipping 11 matching lines @@
     virtual ~Core();
 
     // Initialize the core. Returns true on success.
     bool Init();
 
     // Send a query with a specific rrtype and name. Returns true on success.
     bool SendQuery(uint16 rrtype, std::string name);
 
     // Add/remove a listener to the list of listener. May cause network traffic
     // if listener is active.
-    void AddListener(MDnsListenerImpl* listener, bool alert_existing_records);
+    void AddListener(MDnsListenerImpl* listener);
     void RemoveListener(MDnsListenerImpl* listener);
 
     // Query the cache for records of a specific type and name.
     void QueryCache(uint16 rrtype, const std::string& name,
                     std::vector<const RecordParsed*>* records) const;
 
     // Parse the response and alert relevant listeners.
     virtual void HandlePacket(DnsResponse* response, int bytes_read) OVERRIDE;
 
+    virtual void OnConnectionError(int error) OVERRIDE;
+
    private:
     typedef std::pair<uint16, std::string> ListenerKey;
     typedef std::map<ListenerKey, ObserverList<MDnsListenerImpl>* >
     ListenerMap;
 
     // Alert listeners of an update to the cache.
     void AlertListeners(MDnsUpdateType update_type,
                         const ListenerKey& key, const RecordParsed* record);
 
     // Schedule a cleanup to a specific time, cancelling other cleanups.
@@ skipping 18 matching lines @@
     DISALLOW_COPY_AND_ASSIGN(Core);
   };
 
   MDnsClientImpl();
 
   // Used only for testing. Lets users of this class decouple it from time
   // dependence and network dependence.
   explicit MDnsClientImpl(MDnsConnectionFactory* connection_factory);
   virtual ~MDnsClientImpl();
 
-  // Add delegate for RRType |rrtype| and name |name|.
-  // If |name| is an empty string, listen to all notification of type
-  // |rrtype|.
+  // MDnsClient implementation:
   virtual scoped_ptr<MDnsListener> CreateListener(
       uint16 rrtype,
       const std::string& name,
-      bool active,
-      bool alert_existing_records,
       MDnsListener::Delegate* delegate) OVERRIDE;
 
-  // Create a transaction to Query MDNS for a single-value query
-  // (A, AAAA, TXT, and SRV) asynchronously. May defer to cache.
   virtual scoped_ptr<MDnsTransaction> CreateTransaction(
       uint16 rrtype,
       const std::string& name,
+      int flags,
       const MDnsTransaction::ResultCallback& callback) OVERRIDE;
 
+
   // Functions for testing only.
   bool IsListeningForTests();
 
   bool AddListenRef();
   void SubtractListenRef();
 
   Core* core() { return core_.get(); }
 
  private:
   void Shutdown();
 
   scoped_ptr<Core> core_;
   int listen_refs_;
 
   // Since we can either own or not own the connection_factory, use a scoped_ptr
   // and a ptr.
   scoped_ptr<MDnsConnectionFactory> connection_factory_owned_;
   MDnsConnectionFactory* connection_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MDnsClientImpl);
 };
 
 class MDnsListenerImpl : public MDnsListener,
                          public base::SupportsWeakPtr<MDnsListenerImpl> {
  public:
   MDnsListenerImpl(uint16 rrtype,
                    const std::string& name,
-                   bool active,
-                   bool alert_existing_records,
                    MDnsListener::Delegate* delegate,
                    MDnsClientImpl* client);
 
-  // Destroying the listener stops listening.
   virtual ~MDnsListenerImpl();
 
-  // Start the listener. Returns true on success.
+  // MDnsListener implementation:
   virtual bool Start() OVERRIDE;
 
-  // Get the host or service name for this query.
-  // Return an empty string for no name.
   virtual const std::string& GetName() const OVERRIDE;
 
-  // Get the type for this query (SRV, TXT, A, AAA, etc)
   virtual uint16 GetType() const OVERRIDE;
 
-  virtual bool IsActive() const OVERRIDE;
-
-  // Applies only to listeners with names. Will send out a query for new
-  // information. |force_refresh_cache| will force a refresh of all cached
-  // entities.
-  virtual bool SendQuery(bool force_refresh_cache) OVERRIDE;
-
-  // Applies only to listeners with names. Query mDNS cache synchronously for
-  // either single- or multi- valued records.
-  virtual bool QueryCache(
-      std::vector<const RecordParsed*>* records) const OVERRIDE;
-
   MDnsListener::Delegate* delegate() { return delegate_; }
 
+  // Alert the delegate of a record update.
   void AlertDelegate(MDnsUpdateType update_type,
                      const RecordParsed* record_parsed);
  private:
   uint16 rrtype_;
   std::string name_;
-  bool active_;
-  bool alert_existing_records_;
   MDnsClientImpl* client_;
   MDnsListener::Delegate* delegate_;
 
   bool started_;
   DISALLOW_COPY_AND_ASSIGN(MDnsListenerImpl);
 };
 
-class MDnsTransactionImpl : public MDnsTransaction,
-                            public base::SupportsWeakPtr<MDnsTransactionImpl>,
+class MDnsTransactionImpl : public base::SupportsWeakPtr<MDnsTransactionImpl>,
+                            public MDnsTransaction,
                             public MDnsListener::Delegate {
  public:
   MDnsTransactionImpl(uint16 rrtype,
                       const std::string& name,
+                      int flags,
                       const MDnsTransaction::ResultCallback& callback,
                       MDnsClientImpl* client);
   virtual ~MDnsTransactionImpl();
 
-  // Start the transaction. Returns true on success.
+  // MDnsTransaction implementation:
   virtual bool Start() OVERRIDE;
 
-  // MDnsListener::Delegate implementation
+  virtual const std::string& GetName() const OVERRIDE;
+  virtual uint16 GetType() const OVERRIDE;
+
+  // MDnsListener::Delegate implementation:
   virtual void OnRecordUpdate(MDnsUpdateType update,
                               const RecordParsed* record) OVERRIDE;
   virtual void OnNsecRecord(const std::string& name, unsigned type) OVERRIDE;
 
-  virtual const std::string& GetName() const OVERRIDE;
-  virtual uint16 GetType() const OVERRIDE;
+  virtual void OnCachePurged() OVERRIDE;
+
+  bool is_active() { return !callback_.is_null(); }
+
+  void Reset();

[szym, 2013/06/10 21:58:28]

Make it private.

[Noam Samuel, 2013/06/11 20:35:03]

Done.

 
  private:
   // Trigger the callback and reset all related variables.
   void TriggerCallback(MDnsTransactionResult result,
                        const RecordParsed* record);
 
   // Internal callback for when a cache record is found.
   void CacheRecordFound(const RecordParsed* record);
 
-  // Callback for when the transaction times out.
-  void OnTimedOut();
+  // Signal the transactionis over and release all related resources.
+  void SignalTransactionOver();
 
   uint16 rrtype_;
   std::string name_;
   MDnsTransaction::ResultCallback callback_;
 
   scoped_ptr<MDnsListener> listener_;
   base::CancelableCallback<void()> timeout_;
 
   MDnsClientImpl* client_;
 
   bool started_;
+  int flags_;
 
   DISALLOW_COPY_AND_ASSIGN(MDnsTransactionImpl);
 };
 
 // This implementation of MDnsConnection handles connecting to both IPv4 and
 // IPv6.
 class MDnsConnectionImpl : public MDnsConnection {
  public:
   explicit MDnsConnectionImpl(MDnsConnection::Delegate* delegate);
+  MDnsConnectionImpl(DatagramServerSocket* socket_ipv4,
+                     DatagramServerSocket* socket_ipv6,
+                     MDnsConnection::Delegate* delegate);
+
   virtual ~MDnsConnectionImpl();
 
-  virtual bool Init() OVERRIDE;
-  virtual bool Send(IOBuffer* buffer, unsigned size) OVERRIDE;
+  virtual int Init() OVERRIDE;
+  virtual int Send(IOBuffer* buffer, unsigned size) OVERRIDE;
 
  private:
-  class RecvLoop {
+  class SocketHandler {
    public:
-    RecvLoop(DatagramServerSocket* socket, MDnsConnectionImpl* connection);
-    ~RecvLoop();
-    void DoLoop(int rv);
+    // Pass the socket in. Used for testing.
+    SocketHandler(DatagramServerSocket* socket, MDnsConnectionImpl* connection,
+             const IPEndPoint& multicast_addr);
+    SocketHandler(MDnsConnectionImpl* connection,
+                  const IPEndPoint& multicast_addr);
+    ~SocketHandler();
+    int DoLoop(int rv);
+    int Start();
+
+    int Send(IOBuffer* buffer, unsigned size);
 
    private:
+    int BindSocket();
     void OnDatagramReceived(int rv);
 
+    // Callback for when sending a query has finished.
+    void SendDone(int sent);
+
+    scoped_ptr<DatagramServerSocket> socket_owned_;
     DatagramServerSocket* socket_;
+
     MDnsConnectionImpl* connection_;
     IPEndPoint recv_addr_;
     scoped_ptr<DnsResponse> response_;
+    IPEndPoint multicast_addr_;
   };
-  // Bind a socket with a specific address size to a specific multicast group
-  // and port 5353.
-  bool BindSocket(DatagramServerSocket* socket,
-                  int addr_size,
-                  const char* multicast_group);
 
   // Callback for handling a datagram being recieved on either ipv4 or ipv6.
   // Responsible for ensuring we request another packet from the network.
   void OnDatagramReceived(DatagramServerSocket* socket,
                           DnsResponse* response,
                           IPEndPoint* recv_addr,
                           int bytes_read);
 
-  void OnError(RecvLoop* loop, DatagramServerSocket* socket, int error);
+  void OnError(SocketHandler* loop, int error);
 
-  // Callback for when sending a query has finished.
-  void SendDone(int sent);
+  IPEndPoint GetIPEndPoint(const char* address, int port);
 
-  // The IPEndPoints for sending/recieving packets on IPv4 and IPv6.
-  IPEndPoint GetIPv4SendEndpoint();
-  IPEndPoint GetIPv6SendEndpoint();
-
-  scoped_ptr<DatagramServerSocket> socket_ipv4_;
-  scoped_ptr<DatagramServerSocket> socket_ipv6_;
-
-  RecvLoop loop_ipv4_;
-  RecvLoop loop_ipv6_;
+  SocketHandler socket_handler_ipv4_;
+  SocketHandler socket_handler_ipv6_;
 
   MDnsConnection::Delegate* delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(MDnsConnectionImpl);
 };
 
 class MDnsConnectionImplFactory : public MDnsConnectionFactory {
  public:
   MDnsConnectionImplFactory();
   virtual ~MDnsConnectionImplFactory();
 
   virtual scoped_ptr<MDnsConnection> CreateConnection(
       MDnsConnection::Delegate* delegate) OVERRIDE;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MDnsConnectionImplFactory);
 };
 
 }
 #endif  // NET_DNS_MDNS_CLIENT_IMPL_H_