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 #if NET_2_0
  39         public static class Dns {
  40 #else
  41         public sealed class Dns {
  42
  43                 private Dns () {}
  44 #endif
  45
  46                 static Dns ()
  47                 {
  48                         System.Net.Sockets.Socket.CheckProtocolSupport();
  49                 }
  50
  51                 private delegate IPHostEntry GetHostByNameCallback (string hostName);
  52                 private delegate IPHostEntry ResolveCallback (string hostName);
  53
  54                 public static IAsyncResult BeginGetHostByName (string hostName,
  55                         AsyncCallback requestCallback, object stateObject)
  56                 {
  57                         if (hostName == null)
  58                                 throw new ArgumentNullException ("hostName");
  59
  60                         GetHostByNameCallback c = new GetHostByNameCallback (GetHostByName);
  61                         return c.BeginInvoke (hostName, requestCallback, stateObject);
  62                 }
  63
  64                 public static IAsyncResult BeginResolve (string hostName,
  65                         AsyncCallback requestCallback, object stateObject)
  66                 {
  67                         if (hostName == null)
  68                                 throw new ArgumentNullException ("hostName");
  69
  70                         ResolveCallback c = new ResolveCallback (Resolve);
  71                         return c.BeginInvoke (hostName, requestCallback, stateObject);
  72                 }
  73
  74                 public static IPHostEntry EndGetHostByName (IAsyncResult asyncResult)
  75                 {
  76                         if (asyncResult == null)
  77                                 throw new ArgumentNullException ("asyncResult");
  78
  79                         AsyncResult async = (AsyncResult) asyncResult;
  80                         GetHostByNameCallback cb = (GetHostByNameCallback) async.AsyncDelegate;
  81                         return cb.EndInvoke(asyncResult);
  82                 }
  83
  84                 public static IPHostEntry EndResolve (IAsyncResult asyncResult)
  85                 {
  86                         if (asyncResult == null)
  87                                 throw new ArgumentNullException ("asyncResult");
  88                         AsyncResult async = (AsyncResult) asyncResult;
  89                         ResolveCallback cb = (ResolveCallback) async.AsyncDelegate;
  90                         return cb.EndInvoke(asyncResult);
  91                 }
  92
  93                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  94                 private extern static bool GetHostByName_internal(string host, out string h_name, out string[] h_aliases, out string[] h_addr_list);
  95
  96                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  97                 private extern static bool GetHostByAddr_internal(string addr, out string h_name, out string[] h_aliases, out string[] h_addr_list);
  98
  99                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
 100                 private extern static bool GetHostName_internal(out string h_name);
 101
 102                 private static IPHostEntry hostent_to_IPHostEntry(string h_name, string[] h_aliases, string[] h_addrlist)
 103                 {
 104                         IPHostEntry he = new IPHostEntry();
 105                         ArrayList addrlist = new ArrayList();
 106
 107                         he.HostName = h_name;
 108                         he.Aliases = h_aliases;
 109                         for(int i=0; i<h_addrlist.Length; i++) {
 110                                 try {
 111                                         IPAddress newAddress = IPAddress.Parse(h_addrlist[i]);
 112
 113                                         if( (Socket.SupportsIPv6 && newAddress.AddressFamily == AddressFamily.InterNetworkV6) ||
 114                                             (Socket.SupportsIPv4 && newAddress.AddressFamily == AddressFamily.InterNetwork) )
 115                                                 addrlist.Add(newAddress);
 116                                 } catch (ArgumentNullException) {
 117                                         /* Ignore this, as the
 118                                          * internal call might have
 119                                          * left some blank entries at
 120                                          * the end of the array
 121                                          */
 122                                 }
 123                         }
 124
 125                         if(addrlist.Count == 0)
 126                                 throw new SocketException(11001);
 127
 128                         he.AddressList = addrlist.ToArray(typeof(IPAddress)) as IPAddress[];
 129                         return he;
 130                 }
 131
 132                 public static IPHostEntry GetHostByAddress(IPAddress address)
 133                 {
 134                         if (address == null)
 135                                 throw new ArgumentNullException ("address");
 136
 137                         return GetHostByAddressFromString (address.ToString (), false);
 138                 }
 139
 140                 public static IPHostEntry GetHostByAddress(string address)
 141                 {
 142                         if (address == null)
 143                                 throw new ArgumentNullException ("address");
 144
 145                         return GetHostByAddressFromString (address, true);
 146                 }
 147
 148                 static IPHostEntry GetHostByAddressFromString (string address, bool parse)
 149                 {
 150                         // Undocumented MS behavior: when called with IF_ANY,
 151                         // this should return the local host
 152                         if (address.Equals ("0.0.0.0")) {
 153                                 address = "127.0.0.1";
 154                                 parse = false;
 155                         }
 156
 157                         // Must check the IP format, might send an exception if invalid string.
 158                         if (parse)
 159                                 IPAddress.Parse(address);
 160
 161                         string h_name;
 162                         string[] h_aliases, h_addrlist;
 163
 164                         bool ret = GetHostByAddr_internal(address, out h_name, out h_aliases, out h_addrlist);
 165                         if (!ret)
 166                                 throw new SocketException(11001);
 167
 168                         return (hostent_to_IPHostEntry (h_name, h_aliases, h_addrlist));
 169                 }
 170
 171 #if NET_2_0
 172                 [MonoTODO]
 173                 public static IPHostEntry GetHostEntry (string hostNameOrAddress)
 174                 {
 175                         if (hostNameOrAddress == null)
 176                                 throw new ArgumentNullException ("hostNameOrAddress");
 177
 178                         return Resolve (hostNameOrAddress);
 179                 }
 180 #endif
 181                 public static IPHostEntry GetHostByName(string hostName)
 182                 {
 183                         if (hostName == null)
 184                                 throw new ArgumentNullException();
 185
 186                         string h_name;
 187                         string[] h_aliases, h_addrlist;
 188
 189                         bool ret = GetHostByName_internal(hostName, out h_name,
 190                                 out h_aliases,
 191                                 out h_addrlist);
 192                         if (ret == false)
 193                                 throw new SocketException(11001);
 194
 195                         return(hostent_to_IPHostEntry(h_name, h_aliases,
 196                                 h_addrlist));
 197                 }
 198
 199                 public static string GetHostName()
 200                 {
 201                         string hostName;
 202
 203                         bool ret = GetHostName_internal(out hostName);
 204
 205                         if (ret == false)
 206                                 throw new SocketException(11001);
 207
 208                         return hostName;
 209                 }
 210
 211                 public static IPHostEntry Resolve(string hostName)
 212                 {
 213                         if (hostName == null)
 214                                 throw new ArgumentNullException ("hostName");
 215
 216                         IPHostEntry ret = null;
 217
 218                         try {
 219                                 ret =  GetHostByAddress(hostName);
 220                         }
 221                         catch{}
 222
 223                         if(ret == null)
 224                                 ret =  GetHostByName(hostName);
 225
 226                         return ret;
 227                 }
 228         }
 229 }
 230