public static IPAddress GetExternalAddress()
{
IPHostEntry entry = Dns.GetHostEntry (stunServer);
IPEndPoint endPoint = new IPEndPoint (entry.AddressList [0], 3478);
UdpClient client = new UdpClient ();
client.Connect (endPoint);
MessageHeader header = new MessageHeader ();
header.MessageType = MessageType.BindingRequest;
byte[] bytes = header.GetBytes ();
client.Send (bytes, bytes.Length);
bytes = client.Receive (ref endPoint);
header = new MessageHeader (bytes);
if (header.MessageType == MessageType.BindingResponse) {
foreach (MessageAttribute attribute in header.MessageAttributes) {
if (attribute is MappedAddressAttribute) {
return (attribute as AddressAttributeBase).Address;
}
}
throw new Exception ("Resposne was missing Mapped-address!");
} else {
throw new Exception ("Wrong response message!");
}
}
public static async Task <IPAddress> GetExternalAddressAsync(string server = "stun.ekiga.net")
{
var entry = await Dns.GetHostEntryAsync(server);
var endPoint = new IPEndPoint(entry.AddressList[0], 3478);
IPAddress result = null;
using (var client = new UdpClient())
{
client.Connect(endPoint);
// send
var header = new MessageHeader()
{
MessageType = MessageType.BindingRequest
};
var bytes = header.GetBytes();
await client.SendAsync(bytes, bytes.Length);
// receive
header = new MessageHeader((await client.ReceiveAsync()).Buffer);
if (header.MessageType != MessageType.BindingResponse)
{
throw new Exception("Wrong response message!");
}
// check message
var attr = header.MessageAttributes.OfType <MappedAddressAttribute>().SingleOrDefault();
if (attr == null)
{
throw new Exception("Response was missing Mapped-address!");
}
result = attr.Address;
}
return(result);
}
