feat!: complete IANA reserved block coverage (IPv4 and IPv6)

Add missing IANA reserved blocks:
- IPv4: This network, Loopback, Link-local, IETF Protocol,
  TEST-NET-1/2/3, Benchmarking, Multicast, Reserved, Broadcast
- IPv6: Unspecified, Loopback, IPv4-mapped, IPv4/IPv6 translation,
  TEREDO, Documentation, Unique local, Link-local, Multicast

IsIANAReserved now dispatches by AddressFamily for IPv6 support.

Closes #376

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: lduchosal

src/System.Net.IPNetwork/IPNetwork2IANAblock.cs

@@ -4,75 +4,187 @@
 
 namespace System.Net;
 
+using System.Net.Sockets;
+
 /// <summary>
 /// IANA Blocks.
 /// </summary>
 public sealed partial class IPNetwork2
 {
+    // IPv4 RFC 1918 Private Address Blocks
     private static readonly Lazy<IPNetwork2> IanaAblockReserved = new (() => Parse("10.0.0.0/8"));
     private static readonly Lazy<IPNetwork2> IanaBblockReserved = new (() => Parse("172.16.0.0/12"));
     private static readonly Lazy<IPNetwork2> IanaCblockReserved = new (() => Parse("192.168.0.0/16"));
 
+    // IPv4 Additional IANA Reserved Blocks
+    private static readonly Lazy<IPNetwork2> IanaThisNetwork = new (() => Parse("0.0.0.0/8"));
+    private static readonly Lazy<IPNetwork2> IanaLoopback = new (() => Parse("127.0.0.0/8"));
+    private static readonly Lazy<IPNetwork2> IanaLinkLocal = new (() => Parse("169.254.0.0/16"));
+    private static readonly Lazy<IPNetwork2> IanaIetfProtocol = new (() => Parse("192.0.0.0/24"));
+    private static readonly Lazy<IPNetwork2> IanaTestNet1 = new (() => Parse("192.0.2.0/24"));
+    private static readonly Lazy<IPNetwork2> IanaBenchmark = new (() => Parse("198.18.0.0/15"));
+    private static readonly Lazy<IPNetwork2> IanaTestNet2 = new (() => Parse("198.51.100.0/24"));
+    private static readonly Lazy<IPNetwork2> IanaTestNet3 = new (() => Parse("203.0.113.0/24"));
+    private static readonly Lazy<IPNetwork2> IanaMulticast = new (() => Parse("224.0.0.0/4"));
+    private static readonly Lazy<IPNetwork2> IanaReserved = new (() => Parse("240.0.0.0/4"));
+    private static readonly Lazy<IPNetwork2> IanaBroadcast = new (() => Parse("255.255.255.255/32"));
+
+    // IPv6 IANA Reserved Blocks
+    private static readonly Lazy<IPNetwork2> Iana6Unspecified = new (() => Parse("::/128"));
+    private static readonly Lazy<IPNetwork2> Iana6Loopback = new (() => Parse("::1/128"));
+    private static readonly Lazy<IPNetwork2> Iana6Ipv4Mapped = new (() => Parse("::ffff:0:0/96"));
+    private static readonly Lazy<IPNetwork2> Iana6Ipv4Translation = new (() => Parse("64:ff9b::/96"));
+    private static readonly Lazy<IPNetwork2> Iana6Teredo = new (() => Parse("2001::/32"));
+    private static readonly Lazy<IPNetwork2> Iana6Documentation = new (() => Parse("2001:db8::/32"));
+    private static readonly Lazy<IPNetwork2> Iana6UniqueLocal = new (() => Parse("fc00::/7"));
+    private static readonly Lazy<IPNetwork2> Iana6LinkLocal = new (() => Parse("fe80::/10"));
+    private static readonly Lazy<IPNetwork2> Iana6Multicast = new (() => Parse("ff00::/8"));
+
     /// <summary>
     /// Gets 10.0.0.0/8.
     /// </summary>
     /// <returns>The IANA reserved IPNetwork 10.0.0.0/8.</returns>
-    public static IPNetwork2 IANA_ABLK_RESERVED1
-    {
-        get
-        {
-            return IanaAblockReserved.Value;
-        }
-    }
+    public static IPNetwork2 IANA_ABLK_RESERVED1 => IanaAblockReserved.Value;
 
     /// <summary>
-    /// Gets 172.12.0.0/12.
+    /// Gets 172.16.0.0/12.
     /// </summary>
-    /// <returns>The IANA reserved IPNetwork 172.12.0.0/12.</returns>
-    public static IPNetwork2 IANA_BBLK_RESERVED1
-    {
-        get
-        {
-            return IanaBblockReserved.Value;
-        }
-    }
+    /// <returns>The IANA reserved IPNetwork 172.16.0.0/12.</returns>
+    public static IPNetwork2 IANA_BBLK_RESERVED1 => IanaBblockReserved.Value;
 
     /// <summary>
     /// Gets 192.168.0.0/16.
     /// </summary>
     /// <returns>The IANA reserved IPNetwork 192.168.0.0/16.</returns>
-    public static IPNetwork2 IANA_CBLK_RESERVED1
-    {
-        get
-        {
-            return IanaCblockReserved.Value;
-        }
-    }
+    public static IPNetwork2 IANA_CBLK_RESERVED1 => IanaCblockReserved.Value;
+
+    /// <summary>
+    /// Gets 0.0.0.0/8 (This network).
+    /// </summary>
+    public static IPNetwork2 IANA_THIS_NETWORK => IanaThisNetwork.Value;
+
+    /// <summary>
+    /// Gets 127.0.0.0/8 (Loopback).
+    /// </summary>
+    public static IPNetwork2 IANA_LOOPBACK => IanaLoopback.Value;
+
+    /// <summary>
+    /// Gets 169.254.0.0/16 (Link-local).
+    /// </summary>
+    public static IPNetwork2 IANA_LINK_LOCAL => IanaLinkLocal.Value;
+
+    /// <summary>
+    /// Gets 192.0.0.0/24 (IETF Protocol Assignments).
+    /// </summary>
+    public static IPNetwork2 IANA_IETF_PROTOCOL => IanaIetfProtocol.Value;
+
+    /// <summary>
+    /// Gets 192.0.2.0/24 (Documentation TEST-NET-1).
+    /// </summary>
+    public static IPNetwork2 IANA_TEST_NET1 => IanaTestNet1.Value;
+
+    /// <summary>
+    /// Gets 198.18.0.0/15 (Benchmarking).
+    /// </summary>
+    public static IPNetwork2 IANA_BENCHMARK => IanaBenchmark.Value;
+
+    /// <summary>
+    /// Gets 198.51.100.0/24 (Documentation TEST-NET-2).
+    /// </summary>
+    public static IPNetwork2 IANA_TEST_NET2 => IanaTestNet2.Value;
+
+    /// <summary>
+    /// Gets 203.0.113.0/24 (Documentation TEST-NET-3).
+    /// </summary>
+    public static IPNetwork2 IANA_TEST_NET3 => IanaTestNet3.Value;
+
+    /// <summary>
+    /// Gets 224.0.0.0/4 (Multicast).
+    /// </summary>
+    public static IPNetwork2 IANA_MULTICAST => IanaMulticast.Value;
+
+    /// <summary>
+    /// Gets 240.0.0.0/4 (Reserved).
+    /// </summary>
+    public static IPNetwork2 IANA_RESERVED => IanaReserved.Value;
+
+    /// <summary>
+    /// Gets 255.255.255.255/32 (Broadcast).
+    /// </summary>
+    public static IPNetwork2 IANA_BROADCAST => IanaBroadcast.Value;
+
+    /// <summary>
+    /// Gets ::/128 (Unspecified).
+    /// </summary>
+    public static IPNetwork2 IANA6_UNSPECIFIED => Iana6Unspecified.Value;
+
+    /// <summary>
+    /// Gets ::1/128 (Loopback).
+    /// </summary>
+    public static IPNetwork2 IANA6_LOOPBACK => Iana6Loopback.Value;
+
+    /// <summary>
+    /// Gets ::ffff:0:0/96 (IPv4-mapped).
+    /// </summary>
+    public static IPNetwork2 IANA6_IPV4_MAPPED => Iana6Ipv4Mapped.Value;
+
+    /// <summary>
+    /// Gets 64:ff9b::/96 (IPv4/IPv6 translation).
+    /// </summary>
+    public static IPNetwork2 IANA6_IPV4_TRANSLATION => Iana6Ipv4Translation.Value;
+
+    /// <summary>
+    /// Gets 2001::/32 (TEREDO).
+    /// </summary>
+    public static IPNetwork2 IANA6_TEREDO => Iana6Teredo.Value;
+
+    /// <summary>
+    /// Gets 2001:db8::/32 (Documentation).
+    /// </summary>
+    public static IPNetwork2 IANA6_DOCUMENTATION => Iana6Documentation.Value;
+
+    /// <summary>
+    /// Gets fc00::/7 (Unique local).
+    /// </summary>
+    public static IPNetwork2 IANA6_UNIQUE_LOCAL => Iana6UniqueLocal.Value;
+
+    /// <summary>
+    /// Gets fe80::/10 (Link-local).
+    /// </summary>
+    public static IPNetwork2 IANA6_LINK_LOCAL => Iana6LinkLocal.Value;
+
+    /// <summary>
+    /// Gets ff00::/8 (Multicast).
+    /// </summary>
+    public static IPNetwork2 IANA6_MULTICAST => Iana6Multicast.Value;
 
     /// <summary>
     /// return true if ipaddress is contained in
-    /// IANA_ABLK_RESERVED1, IANA_BBLK_RESERVED1, IANA_CBLK_RESERVED1.
+    /// any IANA reserved block (IPv4 or IPv6).
     /// </summary>
-    /// <param name="ipaddress">A string containing an ip address to convert.</param>
-    /// <returns>true if ipaddress is a IANA reserverd IP Netowkr ; otherwise, false.</returns>
+    /// <param name="ipaddress">An IP address to check.</param>
+    /// <returns>true if ipaddress is in an IANA reserved block; otherwise, false.</returns>
     public static bool IsIANAReserved(IPAddress ipaddress)
     {
         if (ipaddress == null)
         {
             throw new ArgumentNullException(nameof(ipaddress));
         }
 
-        return IANA_ABLK_RESERVED1.Contains(ipaddress)
-               || IANA_BBLK_RESERVED1.Contains(ipaddress)
-               || IANA_CBLK_RESERVED1.Contains(ipaddress);
+        if (ipaddress.AddressFamily == AddressFamily.InterNetworkV6)
+        {
+            return IsIANAReservedIPv6(ipaddress);
+        }
+
+        return IsIANAReservedIPv4(ipaddress);
     }
 
     /// <summary>
     /// return true if ipnetwork is contained in
-    /// IANA_ABLK_RESERVED1, IANA_BBLK_RESERVED1, IANA_CBLK_RESERVED1.
+    /// any IANA reserved block (IPv4 or IPv6).
     /// </summary>
     /// <param name="ipnetwork">The IPNetwork to test.</param>
-    /// <returns>true if the ipnetwork is a IANA reserverd IP Netowkr ; otherwise, false.</returns>
+    /// <returns>true if the ipnetwork is in an IANA reserved block; otherwise, false.</returns>
     public static bool IsIANAReserved(IPNetwork2 ipnetwork)
     {
         if (ipnetwork == null)
@@ -84,14 +196,79 @@ public static bool IsIANAReserved(IPNetwork2 ipnetwork)
     }
 
     /// <summary>
-    /// return true if ipnetwork is contained in
-    /// IANA_ABLK_RESERVED1, IANA_BBLK_RESERVED1, IANA_CBLK_RESERVED1.
+    /// return true if this ipnetwork is contained in
+    /// any IANA reserved block (IPv4 or IPv6).
     /// </summary>
-    /// <returns>true if the ipnetwork is a IANA reserverd IP Netowkr ; otherwise, false.</returns>
+    /// <returns>true if the ipnetwork is in an IANA reserved block; otherwise, false.</returns>
     public bool IsIANAReserved()
     {
-        return IANA_ABLK_RESERVED1.Contains(this)
-               || IANA_BBLK_RESERVED1.Contains(this)
-               || IANA_CBLK_RESERVED1.Contains(this);
+        if (this.family == AddressFamily.InterNetworkV6)
+        {
+            return IsIANAReservedIPv6(this);
+        }
+
+        return IsIANAReservedIPv4(this);
+    }
+
+    private static bool IsIANAReservedIPv4(IPAddress ipaddress)
+    {
+        return IANA_THIS_NETWORK.Contains(ipaddress)
+               || IANA_LOOPBACK.Contains(ipaddress)
+               || IANA_ABLK_RESERVED1.Contains(ipaddress)
+               || IANA_LINK_LOCAL.Contains(ipaddress)
+               || IANA_BBLK_RESERVED1.Contains(ipaddress)
+               || IANA_IETF_PROTOCOL.Contains(ipaddress)
+               || IANA_TEST_NET1.Contains(ipaddress)
+               || IANA_CBLK_RESERVED1.Contains(ipaddress)
+               || IANA_BENCHMARK.Contains(ipaddress)
+               || IANA_TEST_NET2.Contains(ipaddress)
+               || IANA_TEST_NET3.Contains(ipaddress)
+               || IANA_MULTICAST.Contains(ipaddress)
+               || IANA_RESERVED.Contains(ipaddress)
+               || IANA_BROADCAST.Contains(ipaddress);
+    }
+
+    private static bool IsIANAReservedIPv4(IPNetwork2 ipnetwork)
+    {
+        return IANA_THIS_NETWORK.Contains(ipnetwork)
+               || IANA_LOOPBACK.Contains(ipnetwork)
+               || IANA_ABLK_RESERVED1.Contains(ipnetwork)
+               || IANA_LINK_LOCAL.Contains(ipnetwork)
+               || IANA_BBLK_RESERVED1.Contains(ipnetwork)
+               || IANA_IETF_PROTOCOL.Contains(ipnetwork)
+               || IANA_TEST_NET1.Contains(ipnetwork)
+               || IANA_CBLK_RESERVED1.Contains(ipnetwork)
+               || IANA_BENCHMARK.Contains(ipnetwork)
+               || IANA_TEST_NET2.Contains(ipnetwork)
+               || IANA_TEST_NET3.Contains(ipnetwork)
+               || IANA_MULTICAST.Contains(ipnetwork)
+               || IANA_RESERVED.Contains(ipnetwork)
+               || IANA_BROADCAST.Contains(ipnetwork);
+    }
+
+    private static bool IsIANAReservedIPv6(IPAddress ipaddress)
+    {
+        return IANA6_UNSPECIFIED.Contains(ipaddress)
+               || IANA6_LOOPBACK.Contains(ipaddress)
+               || IANA6_IPV4_MAPPED.Contains(ipaddress)
+               || IANA6_IPV4_TRANSLATION.Contains(ipaddress)
+               || IANA6_TEREDO.Contains(ipaddress)
+               || IANA6_DOCUMENTATION.Contains(ipaddress)
+               || IANA6_UNIQUE_LOCAL.Contains(ipaddress)
+               || IANA6_LINK_LOCAL.Contains(ipaddress)
+               || IANA6_MULTICAST.Contains(ipaddress);
+    }
+
+    private static bool IsIANAReservedIPv6(IPNetwork2 ipnetwork)
+    {
+        return IANA6_UNSPECIFIED.Contains(ipnetwork)
+               || IANA6_LOOPBACK.Contains(ipnetwork)
+               || IANA6_IPV4_MAPPED.Contains(ipnetwork)
+               || IANA6_IPV4_TRANSLATION.Contains(ipnetwork)
+               || IANA6_TEREDO.Contains(ipnetwork)
+               || IANA6_DOCUMENTATION.Contains(ipnetwork)
+               || IANA6_UNIQUE_LOCAL.Contains(ipnetwork)
+               || IANA6_LINK_LOCAL.Contains(ipnetwork)
+               || IANA6_MULTICAST.Contains(ipnetwork);
     }
-}
+}