/// <summary>
/// Opens the specified type of active data stream
/// </summary>
/// <param name="type">Type of passive data stream to open</param>
/// <param name="command">The command to execute that requires a data stream</param>
/// <param name="restart">Restart location in bytes for file transfer</param>
/// <returns>A data stream ready to be used</returns>
FtpDataStream OpenActiveDataStream(FtpDataConnectionType type, string command, long restart)
{
FtpTrace.WriteFunc("OpenActiveDataStream", new object[] { type, command, restart });
FtpDataStream stream = new FtpDataStream(this);
FtpReply reply;
#if !CORE
IAsyncResult ar;
#endif
if (m_stream == null)
{
throw new InvalidOperationException("The control connection stream is null! Generally this means there is no connection to the server. Cannot open an active data stream.");
}
if (m_ActivePorts == null || !m_ActivePorts.Any())
{
// Use random port
stream.Listen(m_stream.LocalEndPoint.Address, 0);
}
else
{
var success = false;
// Use one of the specified ports
foreach (var port in m_ActivePorts)
{
try {
stream.Listen(m_stream.LocalEndPoint.Address, port);
success = true;
} catch (SocketException se) {
#if NETFX
// Already in use
if (se.ErrorCode != 10048)
{
throw;
}
#else
throw;
#endif
}
}
// No usable port found
if (!success)
{
throw new Exception("No valid active data port available!");
}
}
#if !CORE
ar = stream.BeginAccept(null, null);
#endif
if (type == FtpDataConnectionType.EPRT || type == FtpDataConnectionType.AutoActive)
{
int ipver = 0;
switch (stream.LocalEndPoint.AddressFamily)
{
case System.Net.Sockets.AddressFamily.InterNetwork:
ipver = 1; // IPv4
break;
case System.Net.Sockets.AddressFamily.InterNetworkV6:
ipver = 2; // IPv6
break;
default:
throw new InvalidOperationException("The IP protocol being used is not supported.");
}
if (!(reply = Execute("EPRT |" + ipver + "|" + GetLocalAddress(stream.LocalEndPoint.Address) + "|" + stream.LocalEndPoint.Port + "|")).Success)
{
// if we're connected with IPv4 and the data channel type is AutoActive then try to fall back to the PORT command
if (reply.Type == FtpResponseType.PermanentNegativeCompletion && type == FtpDataConnectionType.AutoActive && m_stream != null && m_stream.LocalEndPoint.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork)
{
stream.ControlConnection = null; // we don't want this failed EPRT attempt to close our control connection when the stream is closed so clear out the reference.
stream.Close();
return(OpenActiveDataStream(FtpDataConnectionType.PORT, command, restart));
}
else
{
stream.Close();
throw new FtpCommandException(reply);
}
}
}
else
{
if (m_stream.LocalEndPoint.AddressFamily != System.Net.Sockets.AddressFamily.InterNetwork)
{
throw new FtpException("Only IPv4 is supported by the PORT command. Use EPRT instead.");
}
if (!(reply = Execute("PORT " +
GetLocalAddress(stream.LocalEndPoint.Address).Replace('.', ',') + "," +
stream.LocalEndPoint.Port / 256 + "," +
stream.LocalEndPoint.Port % 256)).Success)
{
stream.Close();
throw new FtpCommandException(reply);
}
}
if (restart > 0)
{
if (!(reply = Execute("REST " + restart)).Success)
{
throw new FtpCommandException(reply);
}
}
if (!(reply = Execute(command)).Success)
{
stream.Close();
throw new FtpCommandException(reply);
}
// the command status is used to determine
// if a reply needs to be read from the server
// when the stream is closed so always set it
// otherwise things can get out of sync.
stream.CommandStatus = reply;
#if CORE
stream.AcceptAsync().Wait();
#else
ar.AsyncWaitHandle.WaitOne(m_dataConnectionConnectTimeout);
if (!ar.IsCompleted)
{
stream.Close();
throw new TimeoutException("Timed out waiting for the server to connect to the active data socket.");
}
stream.EndAccept(ar);
#endif
#if !NO_SSL
if (m_dataConnectionEncryption && m_encryptionmode != FtpEncryptionMode.None)
{
stream.ActivateEncryption(m_host,
this.ClientCertificates.Count > 0 ? this.ClientCertificates : null,
m_SslProtocols);
}
#endif
stream.SetSocketOption(System.Net.Sockets.SocketOptionLevel.Socket, System.Net.Sockets.SocketOptionName.KeepAlive, m_keepAlive);
stream.ReadTimeout = m_dataConnectionReadTimeout;
return(stream);
}
