// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.Net.Sockets;
using System.Runtime.InteropServices;
 
internal static partial class Interop
{
    internal static partial class Sys
    {
        internal const int NI_MAXHOST = 1025;
        internal const int NI_MAXSERV = 32;
 
        internal enum GetAddrInfoErrorFlags : int
        {
            EAI_AGAIN = 1,      // Temporary failure in name resolution.
            EAI_BADFLAGS = 2,   // Invalid value for `ai_flags' field.
            EAI_FAIL = 3,       // Non-recoverable failure in name resolution.
            EAI_FAMILY = 4,     // 'ai_family' not supported.
            EAI_NONAME = 5,     // NAME or SERVICE is unknown.
            EAI_BADARG = 6,     // One or more input arguments were invalid.
            EAI_NOMORE = 7,     // No more entries are present in the list.
            EAI_MEMORY = 8,     // Out of memory.
            EAI_SYSTEM = 9,     // Other system error; errno is set to indicate the error.
        }
 
        [StructLayout(LayoutKind.Sequential)]
        internal unsafe struct HostEntry
        {
            internal byte* CanonicalName;      // Canonical Name of the Host
            internal byte** Aliases;           // List of aliases for the host
            internal IPAddress* IPAddressList; // Handle for socket address list
            internal int IPAddressCount;       // Number of IP addresses in the list
        }
 
        [LibraryImport(Libraries.SystemNative, EntryPoint = "SystemNative_GetHostEntryForName", StringMarshalling = StringMarshalling.Utf8)]
        internal static unsafe partial int GetHostEntryForName(string address, AddressFamily family, HostEntry* entry);
 
        [LibraryImport(Libraries.SystemNative, EntryPoint = "SystemNative_FreeHostEntry")]
        internal static unsafe partial void FreeHostEntry(HostEntry* entry);
    }
}