1 files changed, 42 insertions, 0 deletions
diff --git a/Impostor-dev/src/Impostor.Server/Utils/IpUtils.cs b/Impostor-dev/src/Impostor.Server/Utils/IpUtils.cs
new file mode 100644
index 0000000..649d45a
--- /dev/null
+++ b/Impostor-dev/src/Impostor.Server/Utils/IpUtils.cs
@@ -0,0 +1,42 @@
+using System.Linq;
+using System.Net;
+using System.Net.Sockets;
+using Impostor.Api;
+
+namespace Impostor.Server.Utils
+{
+    internal static class IpUtils
+    {
+        public static string ResolveIp(string ip)
+        {
+            // Check if valid ip was entered.
+            if (!IPAddress.TryParse(ip, out var ipAddress))
+            {
+                // Attempt to resolve DNS.
+                try
+                {
+                    var hostAddresses = Dns.GetHostAddresses(ip);
+                    if (hostAddresses.Length == 0)
+                    {
+                        throw new ImpostorConfigException($"Invalid IP Address entered '{ip}'.");
+                    }
+
+                    // Use first IPv4 result.
+                    ipAddress = hostAddresses.First(x => x.AddressFamily == AddressFamily.InterNetwork);
+                }
+                catch (SocketException)
+                {
+                    throw new ImpostorConfigException($"Failed to resolve hostname '{ip}'.");
+                }
+            }
+
+            // Only IPv4.
+            if (ipAddress.AddressFamily == AddressFamily.InterNetworkV6)
+            {
+                throw new ImpostorConfigException($"Invalid IP Address entered '{ipAddress}', only IPv4 is supported by Among Us.");
+            }
+
+            return ipAddress.ToString();
+        }
+    }
+}