ServiceBrowser: to query for multiple services, StartBrowse must be p…

…rovided with all the services at once. This makes it easy to handle the querying for all services together. This combined query also queries for A/AAAA records if the IPAddress for a host is not known.
tmds · Dec 13, 2013 · ca805b9 · ca805b9
1 parent a9f0a07
commit ca805b9
Show file tree

Hide file tree

Showing 3 changed files with 119 additions and 104 deletions.
diff --git a/Tmds/MDns/NetworkInterfaceHandler.cs b/Tmds/MDns/NetworkInterfaceHandler.cs
@@ -32,15 +32,19 @@ public NetworkInterfaceHandler(ServiceBrowser serviceBrowser, NetworkInterface n
             ServiceBrowser = serviceBrowser;
             NetworkInterface = networkInterface;
             _index = NetworkInterface.Information.GetIPProperties().GetIPv4Properties().Index;
+            _queryTimer = new Timer(OnQueryTimerElapsed);
         }
 
-        public void StartBrowse(Name name)
+        public void StartBrowse(IEnumerable<Name> names)
         {
-            var serviceHandler = new ServiceHandler(this, name);
-            _serviceHandlers.Add(name, serviceHandler);
+            foreach (var name in names)
+            {
+                var serviceHandler = new ServiceHandler(this, name);
+                _serviceHandlers.Add(name, serviceHandler);
+            }
             if (_isEnabled)
             {
-                serviceHandler.StartBrowse();
+                StartQuery();
             }
         }
 
@@ -64,11 +68,7 @@ public void Enable()
                 _socket.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.MulticastTimeToLive, 1);
 
                 StartReceive();
-
-                foreach (var serviceHandlerKV in _serviceHandlers)
-                {
-                    serviceHandlerKV.Value.StartBrowse();
-                }
+                StartQuery();
             }
         }
 
@@ -83,10 +83,11 @@ public void Disable()
             {
                 _isEnabled = false;
 
+                StopQuery();
+
                 foreach (var serviceHandlerKV in _serviceHandlers)
                 {
                     ServiceHandler serviceHandler = serviceHandlerKV.Value;
-                    serviceHandler.StopBrowse();
                     serviceHandler.ServiceInfos.Clear();
                 }
 
@@ -188,15 +189,18 @@ private void OnReceive(IAsyncResult ar)
                 var reader = new DnsMessageReader(stream);
                 Header header = reader.ReadHeader();
 
-                if (header.IsQuery && header.QuestionCount == 1 && header.AnswerCount == 0)
+                if (header.IsQuery && header.AnswerCount == 0)
                 {
-                    Question question = reader.ReadQuestion();
-                    Name serviceName = question.QName;
-                    if (_serviceHandlers.ContainsKey(serviceName))
+                    for (int i = 0; i < header.QuestionCount; i++)
                     {
-                        if (header.TransactionID != _serviceHandlers[serviceName].LastTransactionId)
+                        Question question = reader.ReadQuestion();
+                        Name serviceName = question.QName;
+                        if (_serviceHandlers.ContainsKey(serviceName))
                         {
-                            OnServiceQuery(serviceName);
+                            if (header.TransactionID != _lastQueryId)
+                            {
+                                OnServiceQuery(serviceName);
+                            }
                         }
                     }
                 }
@@ -499,6 +503,91 @@ private void AddServiceHostInfo(ServiceInfo service)
             service.Addresses = hostInfo.Addresses;
         }
 
+        private void StartQuery()
+        {
+            _queryCount = 0;
+            ScheduleQueryTimer(0);
+        }
+
+        private void StopQuery()
+        {
+            ScheduleQueryTimer(Timeout.Infinite);
+        }
+
+        private void OnQueryTimerElapsed(object obj)
+        {
+            lock (this)
+            {
+                QueryParameters queryParameters = ServiceBrowser.QueryParameters;
+                DateTime now = DateTime.Now;
+
+                bool sendQuery = false;
+                _lastQueryId = (ushort)_randomGenerator.Next(0, ushort.MaxValue);
+                var writer = new DnsMessageWriter();
+                writer.WriteQueryHeader(_lastQueryId);
+
+                foreach (var serviceKV in _serviceHandlers)
+                {
+                    Name Name = serviceKV.Key;
+                    var ServiceInfos = serviceKV.Value.ServiceInfos;
+                    bool sendQueryForService = false;
+                    if (_queryCount < queryParameters.StartQueryCount)
+                    {
+                        sendQueryForService = true;
+                    }
+                    else
+                    {
+                        if (ServiceInfos.Count == 0)
+                        {
+                            sendQueryForService = true;
+                        }
+                        else
+                        {
+                            foreach (ServiceInfo service in ServiceInfos)
+                            {
+                                if (service.LastQueryTime <= now.AddMilliseconds(-queryParameters.QueryInterval))
+                                {
+                                    sendQueryForService = true;
+                                }
+                            }
+                        }
+                    }
+                    if (sendQueryForService)
+                    {
+                        OnServiceQuery(Name);
+                        writer.WriteQuestion(Name, RecordType.PTR);
+                    }
+                    sendQuery = sendQuery || sendQueryForService;
+                }
+
+                foreach (var hostKV in _hostInfos)
+                {
+                    var name = hostKV.Key;
+                    var adresses = hostKV.Value.Addresses;
+                    if (hostKV.Value.Addresses == null)
+                    {
+                        writer.WriteQuestion(name, RecordType.All);
+                        sendQuery = true;
+                    }
+                }
+
+                if (sendQuery)
+                {
+                    var packets = writer.Packets;
+                    Send(packets);
+
+                    _queryCount++;
+                }
+
+                ScheduleQueryTimer(_queryCount >= queryParameters.StartQueryCount ? queryParameters.QueryInterval : queryParameters.StartQueryInterval);
+            }
+        }
+
+        private void ScheduleQueryTimer(int ms)
+        {
+            _queryTimer.Change(ms, Timeout.Infinite);
+        }
+
         private bool _isEnabled;
         private Socket _socket;
         private readonly int _index;
@@ -508,5 +597,9 @@ private void AddServiceHostInfo(ServiceInfo service)
         private readonly Dictionary<Name, ServiceInfo> _serviceInfos = new Dictionary<Name, ServiceInfo>();
         private readonly Dictionary<Name, HostInfo> _hostInfos = new Dictionary<Name, HostInfo>();
         private readonly Dictionary<Name, ServiceHandler> _serviceHandlers = new Dictionary<Name, ServiceHandler>();
+        private int _queryCount;
+        private readonly Timer _queryTimer;
+        private Random _randomGenerator = new Random();
+        private ushort _lastQueryId;
     }
 }
diff --git a/Tmds/MDns/ServiceBrowser.cs b/Tmds/MDns/ServiceBrowser.cs
@@ -18,6 +18,7 @@
 using System.Collections.Generic;
 using System.Net.NetworkInformation;
 using System.Threading;
+using System.Linq;
 using NetworkInterfaceInformation = System.Net.NetworkInformation.NetworkInterface;
 
 namespace Tmds.MDns
@@ -32,25 +33,19 @@ public ServiceBrowser()
 
         public void StartBrowse(string serviceType)
         {
-            serviceType = serviceType.ToLower();
-
-            if (_serviceTypes.Contains(serviceType))
-            {
-                return;
-            }
-            _serviceTypes.Add(serviceType);
+            StartBrowse(new [] { serviceType });
+        }
 
-            if (!IsBrowsing)
+        public void StartBrowse(IEnumerable<string> serviceTypes)
+        {
+            if (IsBrowsing)
             {
-                StartBrowsing();
+                throw new Exception("Already browsing");
             }
-            var name = new Name(serviceType + ".local.");
-            lock (_interfaceHandlers)
+            StartBrowsing();
+            foreach (var interfaceHandler in _interfaceHandlers)
             {
-                foreach (var interfaceHandler in _interfaceHandlers)
-                {
-                    interfaceHandler.Value.StartBrowse(name);
-                }
+                interfaceHandler.Value.StartBrowse(serviceTypes.Select(st => new Name(st.ToLower() + ".local.")));
             }
         }
 
@@ -241,7 +236,6 @@ private void SynchronizationContextPost(SendOrPostCallback cb)
 
         private readonly HashSet<ServiceAnnouncement> _services = new HashSet<ServiceAnnouncement>();
         private readonly Dictionary<Tuple<string, Name>, ServiceAnnouncement> _serviceAnnouncements = new Dictionary<Tuple<string, Name>, ServiceAnnouncement>();
-        private readonly List<string> _serviceTypes = new List<string>();
         private Dictionary<int, NetworkInterfaceHandler> _interfaceHandlers;
     }
 }
diff --git a/Tmds/MDns/ServiceHandler.cs b/Tmds/MDns/ServiceHandler.cs
@@ -26,83 +26,11 @@ public ServiceHandler(NetworkInterfaceHandler networkInterfaceHandler, Name name
         {
             Name = name;
             NetworkInterfaceHandler = networkInterfaceHandler;
-            _timer = new Timer(OnTimerElapsed);
             ServiceInfos = new List<ServiceInfo>();
         }
 
-        public void StartBrowse()
-        {
-            _queryCount = 0;
-            ScheduleTimer(0);
-        }
-
-        public void StopBrowse()
-        {
-            ScheduleTimer(Timeout.Infinite);
-        }
-
         public Name Name { get; private set; }
         public NetworkInterfaceHandler NetworkInterfaceHandler { get; private set; }
         public List<ServiceInfo> ServiceInfos { get; private set; }
-        public ushort LastTransactionId { get; set; }
-
-        private void OnTimerElapsed(object obj)
-        {
-            lock (NetworkInterfaceHandler)
-            {
-                QueryParameters queryParameters = NetworkInterfaceHandler.ServiceBrowser.QueryParameters;
-                DateTime now = DateTime.Now;
-
-                bool sendQuery = false;
-                if (_queryCount < queryParameters.StartQueryCount)
-                {
-                    sendQuery = true;
-                }
-                else
-                {
-                    if (ServiceInfos.Count == 0)
-                    {
-                        sendQuery = true;
-                    }
-                    else
-                    {
-                        foreach (ServiceInfo service in ServiceInfos)
-                        {
-                            if (service.LastQueryTime <= now.AddMilliseconds(-queryParameters.QueryInterval))
-                            {
-                                sendQuery = true;
-                            }
-                        }
-                    }
-                }
-
-                if (sendQuery)
-                {
-                    NetworkInterfaceHandler.OnServiceQuery(Name);
-                    LastTransactionId = (ushort)_randomGenerator.Next(0, ushort.MaxValue);
-
-                    var writer = new DnsMessageWriter();
-                    writer.WriteQueryHeader(LastTransactionId);
-                    writer.WriteQuestion(Name, RecordType.PTR);
-
-                    var packets = writer.Packets;
-                    NetworkInterfaceHandler.Send(packets);
-
-                    _queryCount++;
-                }
-
-                ScheduleTimer(_queryCount >= queryParameters.StartQueryCount ? queryParameters.QueryInterval : queryParameters.StartQueryInterval);
-            }
-        }
-
-        private void ScheduleTimer(int ms)
-        {
-            _timer.Change(ms, Timeout.Infinite);
-        }
-
-        private int _queryCount;
-        private readonly Timer _timer;
-        private Random _randomGenerator = new Random();
     }
-
 }