net/dns/mdns_client.h

   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_H_
   6 #define NET_DNS_MDNS_CLIENT_H_
   7
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/callback.h"
  12 #include "net/base/ip_endpoint.h"
  13 #include "net/dns/dns_query.h"
  14 #include "net/dns/dns_response.h"
  15 #include "net/dns/record_parsed.h"
  16
  17 namespace net {
  18
  19 class DatagramServerSocket;
  20 class RecordParsed;
  21
  22 // Represents a one-time record lookup. A transaction takes one
  23 // associated callback (see |MDnsClient::CreateTransaction|) and calls it
  24 // whenever a matching record has been found, either from the cache or
  25 // by querying the network (it may choose to query either or both based on its
  26 // creation flags, see MDnsTransactionFlags). Network-based transactions will
  27 // time out after a reasonable number of seconds.
  28 class NET_EXPORT MDnsTransaction {
  29  public:
  30   // Used to signify what type of result the transaction has received.
  31   enum Result {
  32     // Passed whenever a record is found.
  33     RESULT_RECORD,
  34     // The transaction is done. Applies to non-single-valued transactions. Is
  35     // called when the transaction has finished (this is the last call to the
  36     // callback).
  37     RESULT_DONE,
  38     // No results have been found. Applies to single-valued transactions. Is
  39     // called when the transaction has finished without finding any results.
  40     // For transactions that use the network, this happens when a timeout
  41     // occurs, for transactions that are cache-only, this happens when no
  42     // results are in the cache.
  43     RESULT_NO_RESULTS,
  44     // Called when an NSec record is read for this transaction's
  45     // query. This means there cannot possibly be a record of the type
  46     // and name for this transaction.
  47     RESULT_NSEC
  48   };
  49
  50   // Used when creating an MDnsTransaction.
  51   enum Flags {
  52     // Transaction should return only one result, and stop listening after it.
  53     // Note that single result transactions will signal when their timeout is
  54     // reached, whereas multi-result transactions will not.
  55     SINGLE_RESULT = 1 << 0,
  56     // Query the cache or the network. May both be used. One must be present.
  57     QUERY_CACHE = 1 << 1,
  58     QUERY_NETWORK = 1 << 2,
  59     // TODO(noamsml): Add flag for flushing cache when feature is implemented
  60     // Mask of all possible flags on MDnsTransaction.
  61     FLAG_MASK = (1 << 3) - 1,
  62   };
  63
  64   typedef base::Callback<void(Result, const RecordParsed*)>
  65   ResultCallback;
  66
  67   // Destroying the transaction cancels it.
  68   virtual ~MDnsTransaction() {}
  69
  70   // Start the transaction. Return true on success. Cache-based transactions
  71   // will execute the callback synchronously.
  72   virtual bool Start() = 0;
  73
  74   // Get the host or service name for the transaction.
  75   virtual const std::string& GetName() const = 0;
  76
  77   // Get the type for this transaction (SRV, TXT, A, AAA, etc)
  78   virtual uint16 GetType() const = 0;
  79 };
  80
  81 // A listener listens for updates regarding a specific record or set of records.
  82 // Created by the MDnsClient (see |MDnsClient::CreateListener|) and used to keep
  83 // track of listeners.
  84 class NET_EXPORT MDnsListener {
  85  public:
  86   // Used in the MDnsListener delegate to signify what type of change has been
  87   // made to a record.
  88   enum UpdateType {
  89     RECORD_ADDED,
  90     RECORD_CHANGED,
  91     RECORD_REMOVED
  92   };
  93
  94   class Delegate {
  95    public:
  96     virtual ~Delegate() {}
  97
  98     // Called when a record is added, removed or updated.
  99     virtual void OnRecordUpdate(UpdateType update,
 100                                 const RecordParsed* record) = 0;
 101
 102     // Called when a record is marked nonexistent by an NSEC record.
 103     virtual void OnNsecRecord(const std::string& name, unsigned type) = 0;
 104
 105     // Called when the cache is purged (due, for example, ot the network
 106     // disconnecting).
 107     virtual void OnCachePurged() = 0;
 108   };
 109
 110   // Destroying the listener stops listening.
 111   virtual ~MDnsListener() {}
 112
 113   // Start the listener. Return true on success.
 114   virtual bool Start() = 0;
 115
 116   // Actively refresh any received records.
 117   virtual void SetActiveRefresh(bool active_refresh) = 0;
 118
 119   // Get the host or service name for this query.
 120   // Return an empty string for no name.
 121   virtual const std::string& GetName() const = 0;
 122
 123   // Get the type for this query (SRV, TXT, A, AAA, etc)
 124   virtual uint16 GetType() const = 0;
 125 };
 126
 127 // Creates bound datagram sockets ready to use by MDnsClient.
 128 class NET_EXPORT MDnsSocketFactory {
 129  public:
 130   virtual ~MDnsSocketFactory() {}
 131   virtual void CreateSockets(ScopedVector<DatagramServerSocket>* sockets) = 0;
 132
 133   static scoped_ptr<MDnsSocketFactory> CreateDefault();
 134 };
 135
 136 // Listens for Multicast DNS on the local network. You can access information
 137 // regarding multicast DNS either by creating an |MDnsListener| to be notified
 138 // of new records, or by creating an |MDnsTransaction| to look up the value of a
 139 // specific records. When all listeners and active transactions are destroyed,
 140 // the client stops listening on the network and destroys the cache.
 141 class NET_EXPORT MDnsClient {
 142  public:
 143   virtual ~MDnsClient() {}
 144
 145   // Create listener object for RRType |rrtype| and name |name|.
 146   virtual scoped_ptr<MDnsListener> CreateListener(
 147       uint16 rrtype,
 148       const std::string& name,
 149       MDnsListener::Delegate* delegate) = 0;
 150
 151   // Create a transaction that can be used to query either the MDns cache, the
 152   // network, or both for records of type |rrtype| and name |name|. |flags| is
 153   // defined by MDnsTransactionFlags.
 154   virtual scoped_ptr<MDnsTransaction> CreateTransaction(
 155       uint16 rrtype,
 156       const std::string& name,
 157       int flags,
 158       const MDnsTransaction::ResultCallback& callback) = 0;
 159
 160   virtual bool StartListening(MDnsSocketFactory* factory) = 0;
 161
 162   // Do not call this inside callbacks from related MDnsListener and
 163   // MDnsTransaction objects.
 164   virtual void StopListening() = 0;
 165   virtual bool IsListening() const = 0;
 166
 167   // Create the default MDnsClient
 168   static scoped_ptr<MDnsClient> CreateDefault();
 169 };
 170
 171 NET_EXPORT IPEndPoint GetMDnsIPEndPoint(AddressFamily address_family);
 172
 173 typedef std::vector<std::pair<uint32, AddressFamily> > InterfaceIndexFamilyList;
 174 // Returns pairs of interface and address family to bind. Current
 175 // implementation returns unique list of all available interfaces.
 176 NET_EXPORT InterfaceIndexFamilyList GetMDnsInterfacesToBind();
 177
 178 // Create sockets, binds socket to MDns endpoint, and sets multicast interface
 179 // and joins multicast group on for |interface_index|.
 180 // Returns NULL if failed.
 181 NET_EXPORT scoped_ptr<DatagramServerSocket> CreateAndBindMDnsSocket(
 182     AddressFamily address_family,
 183     uint32 interface_index);
 184
 185 }  // namespace net
 186
 187 #endif  // NET_DNS_MDNS_CLIENT_H_