mcs/class/System/System.Net/Dns.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.Net.Sockets;
  31 using System.Text;
  32 using System.Collections;
  33 using System.Threading;
  34 using System.Runtime.CompilerServices;
  35 using System.Runtime.Remoting.Messaging;
  36
  37 namespace System.Net {
  38         public sealed class Dns {
  39
  40                 private Dns () {}
  41                 static Dns ()
  42                 {
  43                         System.Net.Sockets.Socket.CheckProtocolSupport();
  44                 }
  45
  46                 private delegate IPHostEntry GetHostByNameCallback (string hostName);
  47                 private delegate IPHostEntry ResolveCallback (string hostName);
  48
  49                 public static IAsyncResult BeginGetHostByName (string hostName,
  50                         AsyncCallback requestCallback, object stateObject)
  51                 {
  52                         if (hostName == null)
  53                                 throw new ArgumentNullException ("hostName");
  54
  55                         GetHostByNameCallback c = new GetHostByNameCallback (GetHostByName);
  56                         return c.BeginInvoke (hostName, requestCallback, stateObject);
  57                 }
  58
  59                 public static IAsyncResult BeginResolve (string hostName,
  60                         AsyncCallback requestCallback, object stateObject)
  61                 {
  62                         if (hostName == null)
  63                                 throw new ArgumentNullException ("hostName");
  64
  65                         ResolveCallback c = new ResolveCallback (Resolve);
  66                         return c.BeginInvoke (hostName, requestCallback, stateObject);
  67                 }
  68
  69                 public static IPHostEntry EndGetHostByName (IAsyncResult asyncResult)
  70                 {
  71                         if (asyncResult == null)
  72                                 throw new ArgumentNullException ("asyncResult");
  73
  74                         AsyncResult async = (AsyncResult) asyncResult;
  75                         GetHostByNameCallback cb = (GetHostByNameCallback) async.AsyncDelegate;
  76                         return cb.EndInvoke(asyncResult);
  77                 }
  78
  79                 public static IPHostEntry EndResolve (IAsyncResult asyncResult)
  80                 {
  81                         if (asyncResult == null)
  82                                 throw new ArgumentNullException ("asyncResult");
  83                         AsyncResult async = (AsyncResult) asyncResult;
  84                         ResolveCallback cb = (ResolveCallback) async.AsyncDelegate;
  85                         return cb.EndInvoke(asyncResult);
  86                 }
  87
  88                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  89                 private extern static bool GetHostByName_internal(string host, out string h_name, out string[] h_aliases, out string[] h_addr_list);
  90
  91                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  92                 private extern static bool GetHostByAddr_internal(string addr, out string h_name, out string[] h_aliases, out string[] h_addr_list);
  93
  94                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  95                 private extern static bool GetHostName_internal(out string h_name);
  96
  97                 private static IPHostEntry hostent_to_IPHostEntry(string h_name, string[] h_aliases, string[] h_addrlist)
  98                 {
  99                         IPHostEntry he = new IPHostEntry();
 100                         ArrayList addrlist = new ArrayList();
 101
 102                         he.HostName = h_name;
 103                         he.Aliases = h_aliases;
 104                         for(int i=0; i<h_addrlist.Length; i++) {
 105                                 IPAddress newAddress = IPAddress.Parse(h_addrlist[i]);
 106
 107                                 if( (Socket.SupportsIPv6 && newAddress.AddressFamily == AddressFamily.InterNetworkV6) ||
 108                                         (Socket.SupportsIPv4 && newAddress.AddressFamily == AddressFamily.InterNetwork) )
 109                                         addrlist.Add(newAddress);
 110                         }
 111
 112                         if(addrlist.Count == 0)
 113                                 throw new SocketException(11001);
 114
 115                         he.AddressList = addrlist.ToArray(typeof(IPAddress)) as IPAddress[];
 116                         return he;
 117                 }
 118
 119                 public static IPHostEntry GetHostByAddress(IPAddress address)
 120                 {
 121                         if (address == null)
 122                                 throw new ArgumentNullException ("address");
 123
 124                         return GetHostByAddressFromString (address.ToString (), false);
 125                 }
 126
 127                 public static IPHostEntry GetHostByAddress(string address)
 128                 {
 129                         if (address == null)
 130                                 throw new ArgumentNullException ("address");
 131
 132                         return GetHostByAddressFromString (address, true);
 133                 }
 134
 135                 static IPHostEntry GetHostByAddressFromString (string address, bool parse)
 136                 {
 137                         // Undocumented MS behavior: when called with IF_ANY,
 138                         // this should return the local host
 139                         if (address.Equals ("0.0.0.0")) {
 140                                 address = "127.0.0.1";
 141                                 parse = false;
 142                         }
 143
 144                         // Must check the IP format, might send an exception if invalid string.
 145                         if (parse)
 146                                 IPAddress.Parse(address);
 147
 148                         string h_name;
 149                         string[] h_aliases, h_addrlist;
 150
 151                         bool ret = GetHostByAddr_internal(address, out h_name, out h_aliases, out h_addrlist);
 152                         if (!ret)
 153                                 throw new SocketException(11001);
 154
 155                         return (hostent_to_IPHostEntry (h_name, h_aliases, h_addrlist));
 156                 }
 157
 158                 public static IPHostEntry GetHostByName(string hostName)
 159                 {
 160                         if (hostName == null)
 161                                 throw new ArgumentNullException();
 162
 163                         string h_name;
 164                         string[] h_aliases, h_addrlist;
 165
 166                         bool ret = GetHostByName_internal(hostName, out h_name,
 167                                 out h_aliases,
 168                                 out h_addrlist);
 169                         if (ret == false)
 170                                 throw new SocketException(11001);
 171
 172                         return(hostent_to_IPHostEntry(h_name, h_aliases,
 173                                 h_addrlist));
 174                 }
 175
 176                 public static string GetHostName()
 177                 {
 178                         string hostName;
 179
 180                         bool ret = GetHostName_internal(out hostName);
 181
 182                         if (ret == false)
 183                                 throw new SocketException(11001);
 184
 185                         return hostName;
 186                 }
 187
 188                 public static IPHostEntry Resolve(string hostName)
 189                 {
 190                         if (hostName == null)
 191                                 throw new ArgumentNullException ("hostName");
 192
 193                         IPHostEntry ret = null;
 194
 195                         try {
 196                                 ret =  GetHostByAddress(hostName);
 197                         }
 198                         catch{}
 199
 200                         if(ret == null)
 201                                 ret =  GetHostByName(hostName);
 202
 203                         return ret;
 204                 }
 205         }
 206 }
 207