public async Task <IPAddress> GetExternalAddressAsync(CancellationToken cancel_token)
{
int tries = 1;
retry:
cancel_token.ThrowIfCancellationRequested();
using (var client = new UdpClient()) {
var cancel_source = CancellationTokenSource.CreateLinkedTokenSource(
new CancellationTokenSource(250 * tries).Token,
cancel_token);
var cancel = cancel_source.Token;
cancel.Register(() => client.Close(), false);
try {
var bytes = new byte[] { PMPVersion, PMPOpExternalPort };
await client.SendAsync(bytes, bytes.Length, new IPEndPoint(this.DeviceAddress, PMPPort)).ConfigureAwait(false);
var msg = await client.ReceiveAsync().ConfigureAwait(false);
if (!msg.RemoteEndPoint.Address.Equals(this.DeviceAddress) || msg.Buffer.Length < 12)
{
if (tries++ < PMPTries)
{
goto retry;
}
return(null);
}
var ver = BinaryAccessor.GetByte(msg.Buffer, 0);
var opcode = BinaryAccessor.GetByte(msg.Buffer, 1);
var err = BinaryAccessor.GetUInt16BE(msg.Buffer, 2);
var time = BinaryAccessor.GetUInt32BE(msg.Buffer, 4);
var external_ip = BinaryAccessor.GetIPv4AddressBE(msg.Buffer, 8);
if (ver != PMPVersion || opcode != PMPOpResultExternalPort || err != 0)
{
if (tries++ < PMPTries)
{
goto retry;
}
return(null);
}
this.LastTimestamp = time;
return(external_ip);
}
catch (SocketException) { }
catch (ObjectDisposedException) { }
if (tries++ < PMPTries)
{
goto retry;
}
return(null);
}
}
private async Task <MappedPort> MapAsyncInternal(
MappingProtocol protocol,
int port,
int lifetime,
CancellationToken cancel_token)
{
int tries = 1;
retry:
cancel_token.ThrowIfCancellationRequested();
using (var client = new UdpClient())
using (var cancel_source = CancellationTokenSource.CreateLinkedTokenSource(cancel_token))
using (cancel_source.Token.Register(() => client.Close(), false)) {
cancel_source.CancelAfter(250 * tries);
try {
var bytes = new byte[12];
BinaryAccessor.PutByte(bytes, 0, PMPVersion);
switch (protocol)
{
case MappingProtocol.TCP:
BinaryAccessor.PutByte(bytes, 1, PMPOpMapTcp);
break;
case MappingProtocol.UDP:
BinaryAccessor.PutByte(bytes, 1, PMPOpMapUdp);
break;
}
BinaryAccessor.PutUInt16BE(bytes, 2, 0);
BinaryAccessor.PutUInt16BE(bytes, 4, port);
BinaryAccessor.PutUInt16BE(bytes, 6, port);
BinaryAccessor.PutUInt32BE(bytes, 8, lifetime);
await client.SendAsync(bytes, bytes.Length, new IPEndPoint(this.DeviceAddress, PMPPort)).ConfigureAwait(false);
var msg = await client.ReceiveAsync().ConfigureAwait(false);
if (!msg.RemoteEndPoint.Address.Equals(this.DeviceAddress) || msg.Buffer.Length < 16)
{
if (tries++ < PMPTries)
{
goto retry;
}
throw new PortMappingException();
}
var ver = BinaryAccessor.GetByte(msg.Buffer, 0);
var opcode = BinaryAccessor.GetByte(msg.Buffer, 1);
var err = BinaryAccessor.GetUInt16BE(msg.Buffer, 2);
var time = BinaryAccessor.GetUInt32BE(msg.Buffer, 4);
var internal_port = BinaryAccessor.GetUInt16BE(msg.Buffer, 8);
var external_port = BinaryAccessor.GetUInt16BE(msg.Buffer, 10);
var mapped_lifetime = BinaryAccessor.GetUInt32BE(msg.Buffer, 12);
if (ver != PMPVersion)
{
if (tries++ < PMPTries)
{
goto retry;
}
throw new PortMappingException();
}
switch (protocol)
{
case MappingProtocol.TCP:
if (opcode != PMPOpResultMapTcp)
{
if (tries++ < PMPTries)
{
goto retry;
}
throw new PortMappingException();
}
break;
case MappingProtocol.UDP:
if (opcode != PMPOpResultMapUdp)
{
if (tries++ < PMPTries)
{
goto retry;
}
throw new PortMappingException();
}
break;
}
if (err != 0)
{
if (tries++ < PMPTries)
{
goto retry;
}
throw new PortMappingException();
}
this.LastTimestamp = time;
return(new MappedPort(
this,
protocol,
internal_port,
external_port,
DateTime.Now.AddSeconds(mapped_lifetime)));
}
catch (SocketException) { }
catch (ObjectDisposedException) { }
if (tries++ < PMPTries)
{
goto retry;
}
throw new PortMappingException();
}
}
