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Jellyfin.Networking/Manager/NetworkManager.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
 using System.Linq;
 using System.Net;
@@ -380,7 +381,7 @@ namespace Jellyfin.Networking.Manager
                 // Remove all interfaces matching any virtual machine interface prefix
                 if (config.IgnoreVirtualInterfaces)
                 {
-                    // Remove potentially exisiting * and split config string into prefixes
+                    // Remove potentially existing * and split config string into prefixes
                     var virtualInterfacePrefixes = config.VirtualInterfaceNames
                         .Select(i => i.Replace("*", string.Empty, StringComparison.OrdinalIgnoreCase));
 
@@ -587,7 +588,7 @@ namespace Jellyfin.Networking.Manager
         }
 
         /// <inheritdoc/>
-        public bool TryParseInterface(string intf, out IReadOnlyList<IPData> result)
+        public bool TryParseInterface(string intf, [NotNullWhen(true)] out IReadOnlyList<IPData>? result)
         {
             var resultList = new List<IPData>();
             if (string.IsNullOrEmpty(intf) || _interfaces is null)
@@ -660,7 +661,7 @@ namespace Jellyfin.Networking.Manager
         /// <inheritdoc/>
         public IReadOnlyList<IPData> GetLoopbacks()
         {
-            if (!(IsIPv4Enabled && IsIPv4Enabled))
+            if (!IsIPv4Enabled && !IsIPv6Enabled)
             {
                 return Array.Empty<IPData>();
             }

MediaBrowser.Common/Net/INetworkManager.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.Net;
 using System.Net.NetworkInformation;
 using MediaBrowser.Model.Net;
@@ -120,7 +121,7 @@ namespace MediaBrowser.Common.Net
         /// <param name="intf">Interface name.</param>
         /// <param name="result">Resulting object's IP addresses, if successful.</param>
         /// <returns>Success of the operation.</returns>
-        bool TryParseInterface(string intf, out IReadOnlyList<IPData> result);
+        bool TryParseInterface(string intf, [NotNullWhen(true)] out IReadOnlyList<IPData>? result);
 
         /// <summary>
         /// Returns all internal (LAN) bind interface addresses.

MediaBrowser.Common/Net/NetworkExtensions.cs

@@ -166,28 +166,30 @@ namespace MediaBrowser.Common.Net
         /// <param name="result">Collection of <see cref="IPNetwork"/>.</param>
         /// <param name="negated">Boolean signaling if negated or not negated values should be parsed.</param>
         /// <returns><c>True</c> if parsing was successful.</returns>
-        public static bool TryParseToSubnets(string[] values, out List<IPNetwork> result, bool negated = false)
+        public static bool TryParseToSubnets(string[] values, [NotNullWhen(true)] out IReadOnlyList<IPNetwork>? result, bool negated = false)
         {
-            result = new List<IPNetwork>();
-
             if (values is null || values.Length == 0)
             {
+                result = null;
                 return false;
             }
 
+            var tmpResult = new List<IPNetwork>();
             for (int a = 0; a < values.Length; a++)
             {
                 if (TryParseToSubnet(values[a], out var innerResult, negated))
                 {
-                    result.Add(innerResult);
+                    tmpResult.Add(innerResult);
                 }
             }
 
-            if (result.Count > 0)
+            if (tmpResult.Count > 0)
             {
+                result = tmpResult;
                 return true;
             }
 
+            result = null;
             return false;
         }
 
@@ -199,9 +201,8 @@ namespace MediaBrowser.Common.Net
         /// <param name="result">An <see cref="IPNetwork"/>.</param>
         /// <param name="negated">Boolean signaling if negated or not negated values should be parsed.</param>
         /// <returns><c>True</c> if parsing was successful.</returns>
-        public static bool TryParseToSubnet(ReadOnlySpan<char> value, out IPNetwork result, bool negated = false)
+        public static bool TryParseToSubnet(ReadOnlySpan<char> value, [NotNullWhen(true)] out IPNetwork? result, bool negated = false)
         {
-            result = new IPNetwork(IPAddress.None, 32);
             var splitString = value.Trim().Split('/');
             if (splitString.MoveNext())
             {
@@ -224,25 +225,28 @@ namespace MediaBrowser.Common.Net
                         if (int.TryParse(subnetBlock, out var netmask))
                         {
                             result = new IPNetwork(address, netmask);
+                            return true;
                         }
                         else if (IPAddress.TryParse(subnetBlock, out var netmaskAddress))
                         {
                             result = new IPNetwork(address, NetworkExtensions.MaskToCidr(netmaskAddress));
+                            return true;
                         }
                     }
                     else if (address.AddressFamily == AddressFamily.InterNetwork)
                     {
                         result = new IPNetwork(address, 32);
+                        return true;
                     }
                     else if (address.AddressFamily == AddressFamily.InterNetworkV6)
                     {
                         result = new IPNetwork(address, 128);
+                        return true;
                     }
-
-                    return true;
                 }
             }
 
+            result = null;
             return false;
         }
 
@@ -254,11 +258,11 @@ namespace MediaBrowser.Common.Net
         /// <param name="isIPv4Enabled"><c>true</c> if IPv4 is enabled.</param>
         /// <param name="isIPv6Enabled"><c>true</c> if IPv6 is enabled.</param>
         /// <returns><c>true</c> if the parsing is successful, <c>false</c> if not.</returns>
-        public static bool TryParseHost(ReadOnlySpan<char> host, [NotNullWhen(true)] out IPAddress[] addresses, bool isIPv4Enabled = true, bool isIPv6Enabled = false)
+        public static bool TryParseHost(ReadOnlySpan<char> host, [NotNullWhen(true)] out IPAddress[]? addresses, bool isIPv4Enabled = true, bool isIPv6Enabled = false)
         {
             if (host.IsEmpty)
             {
-                addresses = Array.Empty<IPAddress>();
+                addresses = null;
                 return false;
             }
 
@@ -301,9 +305,7 @@ namespace MediaBrowser.Common.Net
                 }
 
                 // Is an IP4 or IP4:port
-                host = hosts[0].Split('/')[0];
-
-                if (IPAddress.TryParse(host, out var address))
+                if (IPAddress.TryParse(hosts[0].AsSpan().LeftPart('/'), out var address))
                 {
                     if (((address.AddressFamily == AddressFamily.InterNetwork) && (!isIPv4Enabled && isIPv6Enabled)) ||
                         ((address.AddressFamily == AddressFamily.InterNetworkV6) && (isIPv4Enabled && !isIPv6Enabled)))
@@ -318,10 +320,9 @@ namespace MediaBrowser.Common.Net
                     return true;
                 }
             }
-            else if (hosts.Count <= 9) // 8 octets + port
+            else if (hosts.Count > 0 && hosts.Count <= 9) // 8 octets + port
             {
-                var splitSpan = host.Split('/');
-                if (splitSpan.MoveNext() && IPAddress.TryParse(splitSpan.Current, out var address))
+                if (IPAddress.TryParse(host.LeftPart('/'), out var address))
                 {
                     addresses = new[] { address };
                     return true;

tests/Jellyfin.Networking.Tests/NetworkParseTests.cs

@@ -203,12 +203,13 @@ namespace Jellyfin.Networking.Tests
             using var nm = new NetworkManager(GetMockConfig(conf), new NullLogger<NetworkManager>());
             NetworkManager.MockNetworkSettings = string.Empty;
 
-            _ = nm.TryParseInterface(result, out IReadOnlyList<IPData>? resultObj);
-
-            // Check to see if dns resolution is working. If not, skip test.
-            _ = NetworkExtensions.TryParseHost(source, out var host);
+            // Check to see if DNS resolution is working. If not, skip test.
+            if (!NetworkExtensions.TryParseHost(source, out var host))
+            {
+                return;
+            }
 
-            if (resultObj is not null && host.Length > 0)
+            if (nm.TryParseInterface(result, out var resultObj))
             {
                 result = resultObj.First().Address.ToString();
                 var intf = nm.GetBindAddress(source, out _);