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();
  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();
  64                         ResolveCallback c = new ResolveCallback (Resolve);
  65                         return c.BeginInvoke (hostName, requestCallback, stateObject);
  66                 }
  67
  68                 public static IPHostEntry EndGetHostByName (IAsyncResult asyncResult) \r
  69                 {
  70                         if (asyncResult == null)
  71                                 throw new ArgumentNullException ("asyncResult");
  72                         AsyncResult async = (AsyncResult) asyncResult;
  73                         GetHostByNameCallback cb = (GetHostByNameCallback) async.AsyncDelegate;
  74                         return cb.EndInvoke(asyncResult);
  75                 }
  76
  77                 public static IPHostEntry EndResolve (IAsyncResult asyncResult) \r
  78                 {
  79                         if (asyncResult == null)
  80                                 throw new ArgumentNullException ("asyncResult");
  81                         AsyncResult async = (AsyncResult) asyncResult;
  82                         ResolveCallback cb = (ResolveCallback) async.AsyncDelegate;
  83                         return cb.EndInvoke(asyncResult);
  84                 }
  85
  86                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  87                 private extern static bool GetHostByName_internal(string host, out string h_name, out string[] h_aliases, out string[] h_addr_list);
  88
  89                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  90                 private extern static bool GetHostByAddr_internal(string addr, out string h_name, out string[] h_aliases, out string[] h_addr_list);
  91
  92                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  93                 private extern static bool GetHostName_internal(out string h_name);
  94
  95                 private static IPHostEntry hostent_to_IPHostEntry(string h_name, string[] h_aliases, string[] h_addrlist) \r
  96                 {
  97                         IPHostEntry he = new IPHostEntry();
  98                         ArrayList addrlist = new ArrayList();
  99
 100                         he.HostName = h_name;
 101                         he.Aliases = h_aliases;
 102                         for(int i=0; i<h_addrlist.Length; i++) {
 103                                 IPAddress newAddress = IPAddress.Parse(h_addrlist[i]);
 104
 105                                 if( (Socket.SupportsIPv6 && newAddress.AddressFamily == AddressFamily.InterNetworkV6) ||
 106                                         (Socket.SupportsIPv4 && newAddress.AddressFamily == AddressFamily.InterNetwork) )
 107                                         addrlist.Add(newAddress);
 108                         }
 109
 110                         if(addrlist.Count == 0)
 111                                 throw new SocketException(11001);
 112
 113                         he.AddressList = addrlist.ToArray(typeof(IPAddress)) as IPAddress[];
 114                         return he;
 115                 }
 116
 117                 public static IPHostEntry GetHostByAddress(IPAddress address) \r
 118                 {
 119                         if (address == null)
 120                                 throw new ArgumentNullException();
 121                         return GetHostByAddress (address.ToString());
 122                 }
 123 \r
 124                 public static IPHostEntry GetHostByAddress(string address) \r
 125                 {
 126                         if (address == null)
 127                                 throw new ArgumentNullException();
 128
 129                         // Undocumented MS behavior: when called with IF_ANY,
 130                         // this should return the local host
 131                         if (address.Equals ("0.0.0.0"))
 132                                 return GetHostByAddress ("127.0.0.1");
 133
 134                         /// Must check the IP format, might send an exception if
 135                         /// invalid string.
 136                         IPAddress.Parse(address);
 137
 138                         string h_name;
 139                         string[] h_aliases, h_addrlist;
 140
 141                         bool ret = GetHostByAddr_internal(address, out h_name,
 142                                 out h_aliases,
 143                                 out h_addrlist);
 144                         if (!ret)
 145                                 throw new SocketException(11001);
 146
 147                         return(hostent_to_IPHostEntry(h_name, h_aliases,
 148                                 h_addrlist));
 149                 }
 150
 151                 public static IPHostEntry GetHostByName(string hostName) \r
 152                 {
 153                         if (hostName == null)
 154                                 throw new ArgumentNullException();
 155
 156                         string h_name;
 157                         string[] h_aliases, h_addrlist;
 158
 159                         bool ret = GetHostByName_internal(hostName, out h_name,
 160                                 out h_aliases,
 161                                 out h_addrlist);
 162                         if (ret == false)
 163                                 throw new SocketException(11001);
 164
 165                         return(hostent_to_IPHostEntry(h_name, h_aliases,
 166                                 h_addrlist));
 167                 }
 168
 169                 /// <summary>
 170                 /// This method returns the host name associated with the local host.
 171                 /// </summary>
 172                 public static string GetHostName() \r
 173                 {
 174                         string hostName;
 175
 176                         bool ret = GetHostName_internal(out hostName);
 177
 178                         if (ret == false)
 179                                 throw new SocketException(11001);
 180
 181                         return hostName;
 182                 }
 183
 184                 /// <summary>
 185                 /// This method resolves a DNS-style host name or IP
 186                 /// address.
 187                 /// </summary>
 188                 /// <param name=hostName>
 189                 /// A string containing either a DNS-style host name (e.g.
 190                 /// www.go-mono.com) or IP address (e.g. 129.250.184.233).
 191                 /// </param>
 192                 public static IPHostEntry Resolve(string hostName) \r
 193                 {
 194                         if (hostName == null)
 195                                 throw new ArgumentNullException();
 196
 197                         IPHostEntry ret = null;
 198
 199                         try {\r
 200                                 ret =  GetHostByAddress(hostName);\r
 201                         }
 202                         catch{}
 203
 204                         if(ret == null)\r
 205                                 ret =  GetHostByName(hostName);\r
 206
 207                         return ret;
 208                 }
 209         }
 210 }
 211