Add reverse dns lookup as a method on InternetAddress.

runtime/bin/socket_patch.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 patch class RawServerSocket  {
   /* patch */ static Future<RawServerSocket> bind(address,
                                                   int port,
                                                   {int backlog: 0,
                                                    bool v6Only: false}) {
     return _RawServerSocket.bind(address, port, backlog, v6Only);
@@ skipping 86 matching lines @@
         return _sockaddr_storage[_IPV4_ADDR_OFFSET] == 169 &&
             _sockaddr_storage[_IPV4_ADDR_OFFSET + 1] == 254;
 
       case InternetAddressType.IP_V6:
         // Checking for fe80::/10.
         return _sockaddr_storage[_IPV6_ADDR_OFFSET] == 0xFE &&
             (_sockaddr_storage[_IPV6_ADDR_OFFSET + 1] & 0xB0) == 0x80;
     }
   }
 
+  Future<InternetAddress> reverse() => _NativeSocket.reverseLookup(this);
+
   _InternetAddress(InternetAddressType this.type,
                    String this.address,
                    String this.host,
                    List<int> this._sockaddr_storage);
 
   factory _InternetAddress.fixed(int id) {
     var sockaddr = _fixed(id);
     switch (id) {
       case _ADDRESS_LOOPBACK_IP_V4:
         return new _InternetAddress(
@@ skipping 67 matching lines @@
   // information on the type of the file descriptor.
   static const int LISTENING_SOCKET = 16;
   static const int PIPE_SOCKET = 17;
   static const int TYPE_NORMAL_SOCKET = 0;
   static const int TYPE_LISTENING_SOCKET = 1 << LISTENING_SOCKET;
   static const int TYPE_PIPE = 1 << PIPE_SOCKET;
 
   // Native port messages.
   static const HOST_NAME_LOOKUP = 0;
   static const LIST_INTERFACES = 1;
+  static const REVERSE_LOOKUP = 2;
 
   // Socket close state
   bool isClosed = false;
   bool isClosedRead = false;
   bool isClosedWrite = false;
   Completer closeCompleter = new Completer();
 
   // Handlers and receive port for socket events from the event handler.
   int eventMask = 0;
   List eventHandlers;
@@ skipping 23 matching lines @@
             throw createError(response, "Failed host name lookup");
           } else {
             return response.skip(1).map((result) {
               var type = new InternetAddressType._from(result[0]);
               return new _InternetAddress(type, result[1], host, result[2]);
             }).toList();
           }
         });
   }
 
+  static Future<InternetAddress> reverseLookup(InternetAddress addr) {
+    ensureSocketService();
+    return socketService.call([REVERSE_LOOKUP, addr._sockaddr_storage])
+        .then((response) {
+          if (isErrorResponse(response)) {
+            throw createError(response, "Failed host name lookup");
+          } else {
+            return addr._cloneWithNewHost(response);
+          }
+        });
+  }
+
   static Future<List<NetworkInterface>> listInterfaces({
       bool includeLoopback: false,
       bool includeLinkLocal: false,
       InternetAddressType type: InternetAddressType.ANY}) {
     ensureSocketService();
     return socketService.call([LIST_INTERFACES, type._value])
         .then((response) {
           if (isErrorResponse(response)) {
             throw createError(response, "Failed listing interfaces");
           } else {
@@ skipping 909 matching lines @@
     if (_detachReady != null) {
       _detachReady.complete(null);
     } else {
       if (_raw != null) {
         _raw.shutdown(SocketDirection.SEND);
         _disableWriteEvent();
       }
     }
   }
 }