cache subnet results

Emby.Server.Implementations/Networking/NetworkManager.cs

@@ -120,20 +120,11 @@ namespace Emby.Server.Implementations.Networking
                 endpoint.StartsWith("169.", StringComparison.OrdinalIgnoreCase)
                 )
             {
-                foreach (NetworkInterface adapter in NetworkInterface.GetAllNetworkInterfaces())
+                var subnets = GetSubnets(endpointFirstPart);
-                {
-                    foreach (UnicastIPAddressInformation unicastIPAddressInformation in adapter.GetIPProperties().UnicastAddresses)
-                    {
-                        if (unicastIPAddressInformation.Address.AddressFamily == AddressFamily.InterNetwork && endpointFirstPart == unicastIPAddressInformation.Address.ToString().Split('.')[0])
-                        {
-                            int subnet_Test = 0;
-                            foreach (string part in unicastIPAddressInformation.IPv4Mask.ToString().Split('.'))
-                            {
-                                if (part.Equals("0")) break;
-                                subnet_Test++;
-                            }
 
-                            var subnet_Match = String.Join(".", unicastIPAddressInformation.Address.ToString().Split('.').Take(subnet_Test).ToArray());
+                foreach (var subnet_Match in subnets)
+                {
+                    //Logger.Debug("subnet_Match:" + subnet_Match);
 
                     if (endpoint.StartsWith(subnet_Match + ".", StringComparison.OrdinalIgnoreCase))
                     {
@@ -141,26 +132,28 @@ namespace Emby.Server.Implementations.Networking
                     }
                 }
             }
-                }
-            }
 
             return false;
         }
 
-        private Dictionary<string, string> _subnetLookup = new Dictionary<string, string>(StringComparer.Ordinal);
+        private Dictionary<string, List<string>> _subnetLookup = new Dictionary<string, List<string>>(StringComparer.Ordinal);
-        private string GetSubnet(string endpointFirstPart)
+        private List<string> GetSubnets(string endpointFirstPart)
         {
-            string subnet_Match = "";
+            List<string> subnets;
 
             lock (_subnetLookup)
             {
-                if (_subnetLookup.TryGetValue(endpointFirstPart, out subnet_Match))
+                if (_subnetLookup.TryGetValue(endpointFirstPart, out subnets))
                 {
-                    return subnet_Match;
+                    return subnets;
                 }
 
+                subnets = new List<string>();
+
                 foreach (NetworkInterface adapter in NetworkInterface.GetAllNetworkInterfaces())
+                {
                     foreach (UnicastIPAddressInformation unicastIPAddressInformation in adapter.GetIPProperties().UnicastAddresses)
+                    {
                         if (unicastIPAddressInformation.Address.AddressFamily == AddressFamily.InterNetwork && endpointFirstPart == unicastIPAddressInformation.Address.ToString().Split('.')[0])
                         {
                             int subnet_Test = 0;
@@ -170,16 +163,21 @@ namespace Emby.Server.Implementations.Networking
                                 subnet_Test++;
                             }
 
-                            subnet_Match = String.Join(".", unicastIPAddressInformation.Address.ToString().Split('.').Take(subnet_Test).ToArray());
+                            var subnet_Match = String.Join(".", unicastIPAddressInformation.Address.ToString().Split('.').Take(subnet_Test).ToArray());
-                        }
 
-                if (!string.IsNullOrWhiteSpace(subnet_Match))
+                            // TODO: Is this check necessary?
+                            if (adapter.OperationalStatus == OperationalStatus.Up)
                             {
-                    _subnetLookup[endpointFirstPart] = subnet_Match;
+                                subnets.Add(subnet_Match);
+                            }
                         }
                     }
+                }
+
+                _subnetLookup[endpointFirstPart] = subnets;
 
-            return subnet_Match;
+                return subnets;
+            }
         }
 
         private bool Is172AddressPrivate(string endpoint)