mcs/class/System.Net/System.Net/Dns_2_1.cs

   1 // System.Net.Dns.cs
   2 //
   3 // Author: Mads Pultz (mpultz@diku.dk)
   4 // Author: Lawrence Pit (loz@cable.a2000.nl)
   5 //
   6 // (C) Mads Pultz, 2001
   7
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 using System;
  30 using System.Collections;
  31 using System.Net.Sockets;
  32 using System.Runtime.CompilerServices;
  33
  34 namespace System.Net {
  35
  36         internal static class Dns {
  37
  38                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  39                 private extern static bool GetHostByName_internal(string host, out string h_name, out string[] h_aliases, out string[] h_addr_list);
  40
  41                 internal static IPAddress [] GetHostAddresses (string hostNameOrAddress)
  42                 {
  43                         if (hostNameOrAddress == null)
  44                                 throw new ArgumentNullException ("hostNameOrAddress");
  45
  46                         if (hostNameOrAddress == "0.0.0.0" || hostNameOrAddress == "::0")
  47                                 throw new ArgumentException ("Addresses 0.0.0.0 (IPv4) " +
  48                                         "and ::0 (IPv6) are unspecified addresses. You " +
  49                                         "cannot use them as target address.",
  50                                         "hostNameOrAddress");
  51
  52                         IPAddress addr;
  53                         if (hostNameOrAddress.Length > 0 && IPAddress.TryParse (hostNameOrAddress, out addr))
  54                                 return new IPAddress[1] { addr };
  55
  56                         string h_name;
  57                         string[] h_aliases, h_addrlist;
  58
  59                         bool ret = GetHostByName_internal (hostNameOrAddress, out h_name, out h_aliases, out h_addrlist);
  60                         if (ret == false)
  61                                 throw new SocketException(11001);
  62
  63                         IPHostEntry entry = hostent_to_IPHostEntry (h_name, h_aliases, h_addrlist);
  64                         return entry.AddressList;
  65                 }
  66
  67                 private static IPHostEntry hostent_to_IPHostEntry(string h_name, string[] h_aliases, string[] h_addrlist)
  68                 {
  69                         IPHostEntry he = new IPHostEntry();
  70                         ArrayList addrlist = new ArrayList();
  71
  72                         he.HostName = h_name;
  73                         he.Aliases = h_aliases;
  74                         for(int i=0; i<h_addrlist.Length; i++) {
  75                                 try {
  76                                         IPAddress newAddress = IPAddress.Parse(h_addrlist[i]);
  77
  78                                         if( (Socket.SupportsIPv6 && newAddress.AddressFamily == AddressFamily.InterNetworkV6) ||
  79                                             (Socket.SupportsIPv4 && newAddress.AddressFamily == AddressFamily.InterNetwork) )
  80                                                 addrlist.Add(newAddress);
  81                                 } catch (ArgumentNullException) {
  82                                         /* Ignore this, as the
  83                                          * internal call might have
  84                                          * left some blank entries at
  85                                          * the end of the array
  86                                          */
  87                                 }
  88                         }
  89
  90                         if(addrlist.Count == 0)
  91                                 throw new SocketException(11001);
  92
  93                         he.AddressList = addrlist.ToArray(typeof(IPAddress)) as IPAddress[];
  94                         return he;
  95                 }
  96         }
  97 }
  98