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69 lines
2.3 KiB
C#
69 lines
2.3 KiB
C#
using System.Net.Sockets;
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using System.Net;
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using System.Threading.Tasks;
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namespace Sandbox;
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public static partial class SandboxSystemExtensions
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{
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/// <summary>
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/// Does this Uri resolve to a private range IP address?
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/// </summary>
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internal static bool IsPrivate( this Uri uri )
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{
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return Dns.GetHostEntry( uri.DnsSafeHost ).AddressList.Any( x => x.IsPrivate() );
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}
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/// <summary>
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/// Does this Uri resolve to a private range IP address?
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/// </summary>
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internal static async Task<bool> IsPrivateAsync( this Uri uri )
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{
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var entry = await Dns.GetHostEntryAsync( uri.DnsSafeHost );
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return entry.AddressList.Any( x => x.IsPrivate() );
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}
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/// <summary>
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/// Returns true if the IP address is in a private range.<br/>
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/// IPv4: Loopback, link local ("169.254.x.x"), class A ("10.x.x.x"), class B ("172.16.x.x" to "172.31.x.x") and class C ("192.168.x.x").<br/>
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/// IPv6: Loopback, link local, site local, unique local and private IPv4 mapped to IPv6.<br/>
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/// </summary>
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internal static bool IsPrivate( this IPAddress ip )
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{
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// Map back to IPv4 if mapped to IPv6, for example "::ffff:1.2.3.4" to "1.2.3.4".
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if ( ip.IsIPv4MappedToIPv6 )
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ip = ip.MapToIPv4();
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// Checks loopback ranges for both IPv4 and IPv6.
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if ( IPAddress.IsLoopback( ip ) ) return true;
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// IPv4
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if ( ip.AddressFamily == AddressFamily.InterNetwork )
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{
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var ipv4Bytes = ip.GetAddressBytes();
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// Link local (no IP assigned by DHCP): 169.254.0.0 to 169.254.255.255 (169.254.0.0/16)
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bool IsLinkLocal() => ipv4Bytes[0] == 169 && ipv4Bytes[1] == 254;
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// Class A private range: 10.0.0.0 – 10.255.255.255 (10.0.0.0/8)
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bool IsClassA() => ipv4Bytes[0] == 10;
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// Class B private range: 172.16.0.0 – 172.31.255.255 (172.16.0.0/12)
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bool IsClassB() => ipv4Bytes[0] == 172 && ipv4Bytes[1] >= 16 && ipv4Bytes[1] <= 31;
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// Class C private range: 192.168.0.0 – 192.168.255.255 (192.168.0.0/16)
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bool IsClassC() => ipv4Bytes[0] == 192 && ipv4Bytes[1] == 168;
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return IsLinkLocal() || IsClassA() || IsClassC() || IsClassB();
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}
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// IPv6
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if ( ip.AddressFamily == AddressFamily.InterNetworkV6 )
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{
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return ip.IsIPv6LinkLocal || ip.IsIPv6UniqueLocal || ip.IsIPv6SiteLocal;
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}
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throw new NotSupportedException( $"IP address family {ip.AddressFamily} is not supported, expected only IPv4 (InterNetwork) or IPv6 (InterNetworkV6)" );
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}
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}
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