1 files changed, 158 insertions, 0 deletions
diff --git a/Tools/Hazel-Networking/Hazel/UPnP/NetUtility.cs b/Tools/Hazel-Networking/Hazel/UPnP/NetUtility.cs
new file mode 100644
index 0000000..d856823
--- /dev/null
+++ b/Tools/Hazel-Networking/Hazel/UPnP/NetUtility.cs
@@ -0,0 +1,158 @@
+using System;
+using System.Collections.Generic;
+using System.Net;
+using System.Net.NetworkInformation;
+using System.Net.Sockets;
+
+namespace Hazel.UPnP
+{
+    internal class NetUtility
+    {
+        private static IList<NetworkInterface> GetValidNetworkInterfaces()
+        {
+            var nics = NetworkInterface.GetAllNetworkInterfaces();
+            if (nics == null || nics.Length < 1)
+                return new NetworkInterface[0];
+
+            var validInterfaces = new List<NetworkInterface>(nics.Length);
+
+            NetworkInterface best = null;
+            foreach (NetworkInterface adapter in nics)
+            {
+                if (adapter.NetworkInterfaceType == NetworkInterfaceType.Loopback || adapter.NetworkInterfaceType == NetworkInterfaceType.Unknown)
+                    continue;
+                if (!adapter.Supports(NetworkInterfaceComponent.IPv4) && !adapter.Supports(NetworkInterfaceComponent.IPv6))
+                    continue;
+                if (best == null)
+                    best = adapter;
+                if (adapter.OperationalStatus != OperationalStatus.Up)
+                    continue;
+
+                // make sure this adapter has any ip addresses
+                IPInterfaceProperties properties = adapter.GetIPProperties();
+                foreach (UnicastIPAddressInformation unicastAddress in properties.UnicastAddresses)
+                {
+                    if (unicastAddress != null && unicastAddress.Address != null)
+                    {
+                        // Yes it does, add this network interface.
+                        validInterfaces.Add(adapter);
+                        break;
+                    }
+                }
+            }
+
+            if (validInterfaces.Count == 0 && best != null)
+                validInterfaces.Add(best);
+
+            return validInterfaces;
+        }
+
+        /// <summary>
+        /// Gets the addresses from all active network interfaces, but at most one per interface.
+        /// </summary>
+        /// <param name="addressFamily">The <see cref="AddressFamily"/> of the addresses to return</param>
+        /// <returns>An <see cref="ICollection{T}"/> of <see cref="UnicastIPAddressInformation"/>.</returns>
+        public static ICollection<UnicastIPAddressInformation> GetAddressesFromNetworkInterfaces(AddressFamily addressFamily)
+        {
+            var unicastAddresses = new List<UnicastIPAddressInformation>();
+
+            foreach (NetworkInterface adapter in GetValidNetworkInterfaces())
+            {
+                IPInterfaceProperties properties = adapter.GetIPProperties();
+                foreach (UnicastIPAddressInformation unicastAddress in properties.UnicastAddresses)
+                {
+                    if (unicastAddress != null && unicastAddress.Address != null && unicastAddress.Address.AddressFamily == addressFamily)
+                    {
+                        unicastAddresses.Add(unicastAddress);
+                        break;
+                    }
+                }
+            }
+
+            return unicastAddresses;
+        }
+
+        /// <summary>
+        /// Gets my local IPv4 address (not necessarily external) and subnet mask
+        /// </summary>
+        public static IPAddress GetMyAddress(out IPAddress mask)
+        {
+            var networkInterfaces = GetValidNetworkInterfaces();
+            IPInterfaceProperties properties = null;
+
+            if (networkInterfaces.Count > 0)
+                properties = networkInterfaces[0]?.GetIPProperties();
+
+            if (properties != null)
+            {
+                foreach (UnicastIPAddressInformation unicastAddress in properties.UnicastAddresses)
+                {
+                    if (unicastAddress != null && unicastAddress.Address != null && unicastAddress.Address.AddressFamily == AddressFamily.InterNetwork)
+                    {
+                        mask = unicastAddress.IPv4Mask;
+                        return unicastAddress.Address;
+                    }
+                }
+            }
+
+            mask = null;
+            return null;
+        }
+
+        /// <summary>
+        /// Gets the broadcast address for the first network interface or, if not able to,
+        /// the limited broadcast address.
+        /// </summary>
+        /// <returns>An <see cref="IPAddress"/> for broadcasting.</returns>
+        public static IPAddress GetBroadcastAddress()
+        {
+            var networkInterfaces = GetValidNetworkInterfaces();
+            IPInterfaceProperties properties = null;
+
+            if (networkInterfaces.Count > 0)
+                properties = networkInterfaces[0]?.GetIPProperties();
+
+            if (properties != null)
+            {
+                foreach (UnicastIPAddressInformation unicastAddress in properties.UnicastAddresses)
+                {
+                    IPAddress ipAddress = GetBroadcastAddress(unicastAddress);
+                    if (ipAddress != null)
+                    {
+                        return ipAddress;
+                    }
+                }
+            }
+            
+            return IPAddress.Broadcast;
+        }
+
+        /// <summary>
+        /// Gets the broadcast address for the given <paramref name="unicastAddress"/>.
+        /// </summary>
+        /// <param name="unicastAddress">A <see cref="UnicastIPAddressInformation"/></param>
+        /// <returns>An <see cref="IPAddress"/> for broadcasting, null if the <paramref name="unicastAddress"/>
+        /// is not an IPv4 address.</returns>
+        public static IPAddress GetBroadcastAddress(UnicastIPAddressInformation unicastAddress)
+        {
+            if (unicastAddress != null && unicastAddress.Address != null && unicastAddress.Address.AddressFamily == AddressFamily.InterNetwork)
+            {
+                var mask = unicastAddress.IPv4Mask;
+                byte[] ipAdressBytes = unicastAddress.Address.GetAddressBytes();
+                byte[] subnetMaskBytes = mask.GetAddressBytes();
+
+                if (ipAdressBytes.Length != subnetMaskBytes.Length)
+                    throw new ArgumentException("Lengths of IP address and subnet mask do not match.");
+
+                byte[] broadcastAddress = new byte[ipAdressBytes.Length];
+                for (int i = 0; i < broadcastAddress.Length; i++)
+                {
+                    broadcastAddress[i] = (byte)(ipAdressBytes[i] | (subnetMaskBytes[i] ^ 255));
+                }
+                return new IPAddress(broadcastAddress);
+            }
+
+            return null;
+        }
+    }
+}