Added some IP address improvements

src/AMWD.Common/Extensions/IPAddressExtensions.cs

@@ -1,4 +1,7 @@
-namespace System.Net
+using System.Linq;
+using System.Net.Sockets;
+
+namespace System.Net
 {
 	/// <summary>
 	/// Provides extension methods for <see cref="IPAddress"/>es.
@@ -48,5 +51,90 @@
 
 			return new IPAddress(bytes);
 		}
+
+		/// <summary>
+		/// Converts an <see cref="IPAddress"/> to a clean string representation.
+		/// </summary>
+		/// <param name="ipAddress">The <see cref="IPAddress"/> to convert.</param>
+		/// <returns>A clean string representation of the <see cref="IPAddress"/>.</returns>
+		public static string ToCleanString(this IPAddress ipAddress)
+		{
+			string address = ipAddress.ToString();
+			if (ipAddress.IsIPv4MappedToIPv6)
+				address = ipAddress.MapToIPv4().ToString();
+
+			return address;
+		}
+
+		/// <summary>
+		/// Converts a prefix length to a subnet mask (IPv4 only).
+		/// </summary>
+		/// <param name="prefixLength">The prefix length.</param>
+		public static IPAddress ToSubnetMask(this int prefixLength)
+		{
+			if (prefixLength < 0 || prefixLength > 32)
+				throw new ArgumentOutOfRangeException(nameof(prefixLength));
+
+			byte[] bytes = new byte[4];
+			for (int i = 0; i < prefixLength; i++)
+			{
+				int byteIndex = i / 8;
+				int bitIndex = 7 - (i % 8);
+				bytes[byteIndex] |= (byte)(1 << bitIndex);
+			}
+
+			return new IPAddress(bytes);
+		}
+
+		/// <summary>
+		/// Obfuscates an IP address by masking portions of it to conceal sensitive information.
+		/// </summary>
+		/// <remarks>
+		/// This method replaces parts of the IP address with a masking character to help prevent exposure of
+		/// full address details in logs or user interfaces. For IPv4-mapped IPv6 addresses, the address is first converted to
+		/// its IPv4 equivalent before obfuscation. Loopback addresses (<c>127.0.0.1</c> and <c>::1</c>) are not obfuscated.
+		/// </remarks>
+		/// <param name="address">The IP address to obfuscate.</param>
+		/// <param name="obfuscation">The char (or string) to obfuscate with.</param>
+		/// <returns>
+		/// A string representation of the obfuscated IP address. For loopback addresses, the original address is returned unmodified.
+		/// </returns>
+		public static string ObfuscateIpAddress(this IPAddress address, string obfuscation = "•")
+		{
+			string[] addressParts;
+			string delimiter;
+			switch (address.AddressFamily)
+			{
+				case AddressFamily.InterNetwork:
+					if (address.ToString() == "127.0.0.1")
+						return address.ToString();
+
+					delimiter = ".";
+					addressParts = address.ToString().Split(delimiter.First());
+					break;
+
+				case AddressFamily.InterNetworkV6:
+					if (address.IsIPv4MappedToIPv6)
+						return address.MapToIPv4().ObfuscateIpAddress(obfuscation);
+
+					if (address.ToString() == "::1")
+						return address.ToString();
+
+					delimiter = ":";
+					addressParts = address.ToString().Split(delimiter.First());
+					break;
+
+				default:
+					return address.ToString();
+			}
+
+			for (int i = 0; i < addressParts.Length; i++)
+			{
+				if (i % 2 == 0)
+					addressParts[i] = obfuscation;
+			}
+
+			return string.Join(delimiter, addressParts);
+		}
 	}
 }