public static IPAddress QueryActiveIPAddress(int timeout = 300, string hostNameOrAddress = "www.baidu.com")
{
if (string.IsNullOrEmpty(hostNameOrAddress))
{
return(null);
}
using (AutoResetEvent events = new AutoResetEvent(false))
{
IPAddress address = null;
Stopwatch stopwatch = new Stopwatch();
bool istimedout = false;
try
{
Dns.BeginGetHostAddresses(hostNameOrAddress, (ar) =>
{
if (istimedout)
{
return;
}
try
{
IPAddress[] addresses = Dns.EndGetHostAddresses(ar);
if (addresses != null && addresses.Length > 0)
{
foreach (IPAddress i in addresses)
{
if (i.AddressFamily == AddressFamily.InterNetwork)
{
address = i;
break;
}
}
events.Set();
}
}
catch (Exception)
{
}
}, null);
}
catch (Exception)
{
return(null);
}
do
{
stopwatch.Start();
if (!events.WaitOne(timeout))
{
istimedout = true;
return(null);
}
else if (address == null)
{
return(null);
}
stopwatch.Stop();
} while (false);
timeout -= Convert.ToInt32(stopwatch.ElapsedMilliseconds);
if (timeout <= 0)
{
return(null);
}
using (Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
{
try
{
socket.NoDelay = true;
socket.BeginConnect(new IPEndPoint(address, 443), (ar) =>
{
if (istimedout)
{
return;
}
try
{
socket.EndConnect(ar);
EndPoint localEP = socket.LocalEndPoint;
if (localEP != null)
{
IPEndPoint ipep = (IPEndPoint)localEP;
address = ipep.Address;
events.Set();
}
}
catch (Exception)
{
address = null;
}
}, null);
}
catch (Exception)
{
return(null);
}
do
{
if (!events.WaitOne(timeout))
{
istimedout = true;
return(null);
}
} while (false);
MalockSocket.Close(socket);
}
return(address);
}
}
