Fix bug where Extract with an "Any" network would throw. Also fix an …

…incorrect exception being thrown on AddressFamily mismatch.

IPNetworkHelper.Tests/NetworkHelperTests.cs

@@ -114,7 +114,7 @@ public void SplitThrowsOnUnsplittableNetworkIPv6()
 
 
     [TestMethod]
-    [ExpectedException(typeof(IPNetworkNotInIPNetworkException))]
+    [ExpectedException(typeof(AddressFamilyMismatchException))]
     public void ExtractThrowsOnAddressFamilyMismatch()
     {
         var ipv4 = IPNetwork.Parse("192.168.0.0/24");
@@ -143,6 +143,16 @@ public void ExtractThrowsOnDifferentNetwork()
         network.Extract(different).ToArray();
     }
 
+    [TestMethod]
+    public void ExtractIPv4Prefix()
+    {
+        var network = IPNetwork.Parse("192.168.0.0/16");
+
+        var result = network.Extract(20).ToArray();
+
+        Assert.IsTrue(result.Length == 5);
+    }
+
     [TestMethod]
     public void ExtractIPv4()
     {
@@ -167,6 +177,16 @@ public void ExtractSelfReturnsSelfIPv4()
         Assert.IsTrue(result.Select((n, i) => expected[i].Equals(n)).All(v => true));
     }
 
+    [TestMethod]
+    public void ExtractIPv6Prefix()
+    {
+        var network = IPNetwork.Parse("1111:2222::/32");
+
+        var result = network.Extract(64).ToArray();
+
+        Assert.IsTrue(result.Length == 33);
+    }
+
     [TestMethod]
     public void ExtractIPv6()
     {

IPNetworkHelper/NetworkHelper.cs

@@ -127,7 +127,7 @@ public static IEnumerable<IPNetwork> Extract(this IPNetwork network, int prefixL
     /// <param name="desiredNetwork">The subnet to extract from the network.</param>
     /// <returns>Returns all subnets after taking the desired subnet, including the desired subnet.</returns>
     public static IEnumerable<IPNetwork> Extract(this IPNetwork network, IPNetwork desiredNetwork)
-        => Extract(network, [desiredNetwork]);
+        => ExtractImpl(network, desiredNetwork).OrderBy(i => i, IPNetworkComparer.Default);
 
     /// <summary>
     /// Extracts the given subnets from the network and returns all subnets after taking the desired subnet, including the desired subnets.