/// <summary>
/// Connects to a FTP server using the provided parameters.
/// The default representation tipe is set to Binary.
/// The text encoding is set to UTF8, if supported by the server via the FEAT command.
/// </summary>
/// <param name="hostname"></param>
/// <param name="port"></param>
/// <param name="credential"></param>
/// <param name="sslSupportMode"></param>
/// <param name="userValidateServerCertificate"></param>
/// <param name="x509ClientCert"></param>
/// <param name="sslMinKeyExchangeAlgStrength"></param>
/// <param name="sslMinCipherAlgStrength"></param>
/// <param name="sslMinHashAlgStrength"></param>
/// <param name="timeout">Connection timeout in ms. <c>null</c> can be specifiad to keep the default value of 120s.</param>
/// <param name="useCtrlEndPointAddressForData"><c>true</c> to use the control channel remote address for data connections instead of the address returned by PASV</param>
/// <param name="dataConnectionMode">Active or Passive data connection mode</param>
/// <returns>The text of the \"welcome message\" sent by the server.</returns>
public string Connect(string hostname, int port, NetworkCredential credential, ESSLSupportMode sslSupportMode,
RemoteCertificateValidationCallback userValidateServerCertificate, X509Certificate x509ClientCert,
int sslMinKeyExchangeAlgStrength, int sslMinCipherAlgStrength, int sslMinHashAlgStrength,
int? timeout, bool useCtrlEndPointAddressForData, EDataConnectionMode dataConnectionMode)
{
Close();
// Anonymous authentication
if (credential == null)
credential = new NetworkCredential(anonUsername, anonPassword);
if (timeout != null)
this.timeout = timeout.Value;
this.sslClientCert = x509ClientCert;
this.userValidateServerCertificate = userValidateServerCertificate;
this.sslMinKeyExchangeAlgStrength = sslMinKeyExchangeAlgStrength;
this.sslMinCipherAlgStrength = sslMinCipherAlgStrength;
this.sslMinHashAlgStrength = sslMinHashAlgStrength;
this.sslSupportRequestedMode = sslSupportMode;
this.sslSupportCurrentMode = sslSupportMode;
this.useCtrlEndPointAddressForData = useCtrlEndPointAddressForData;
this.dataConnectionMode = dataConnectionMode;
sslInfo = null;
features = null;
transferMode = ETransferMode.ASCII;
textEncoding = ETextEncoding.ASCII;
bannerMessage = null;
welcomeMessage = null;
currDirStack.Clear();
// Ok, member initialization is done. Start with setting up a control connection
SetupCtrlConnection(hostname, port, Encoding.ASCII);
// Used later for SSL/TLS auth
this.hostname = hostname;
// Implicit SSL/TLS
bool isImplicitSsl = (sslSupportMode & ESSLSupportMode.Implicit) == ESSLSupportMode.Implicit;
if (isImplicitSsl)
SwitchCtrlToSSLMode();
// Wait fot server message
bannerMessage = GetReply().Message;
// Explicit SSL/TLS
if (!isImplicitSsl)
SslControlChannelCheckExplicitEncryptionRequest(sslSupportMode);
// Login. Note that a password might not be required
// TODO: check if the welcomeMessage is returned by the USER command in case the PASS command is not required.
if(UserCmd(credential.UserName))
welcomeMessage = PassCmd(credential.Password);
GetFeaturesFromServer();
if (IsControlChannelEncrypted)
if(!isImplicitSsl)
{
SslDataChannelCheckExplicitEncryptionRequest();
if ((sslSupportMode & ESSLSupportMode.ControlChannelRequested) != ESSLSupportMode.ControlChannelRequested)
SSlCtrlChannelCheckRevertToClearText();
}
else
SslDataChannelImplicitEncryptionRequest();
try
{
// This is required by some FTP servers and must precede any OPTS command
if (CheckFeature("CLNT"))
ClntCmd(clntName);
// Set UTF8 as character encoding, but only if listed among the FEAT features
if (CheckFeature("UTF8"))
SetTextEncoding(ETextEncoding.UTF8);
}
catch (Exception)
{
//TODO: add warning info
}
// Default binary transfers
SetTransferMode(ETransferMode.Binary);
return welcomeMessage;
}
/// <summary>
/// Copies the protocol information form the given stream.
/// </summary>
/// <param name="sslStream"></param>
private void SetSslInfo(SslStream sslStream)
{
sslInfo = new SslInfo()
{
SslProtocol = sslStream.SslProtocol,
CipherAlgorithm = sslStream.CipherAlgorithm,
CipherStrength = sslStream.CipherStrength,
HashAlgorithm = sslStream.HashAlgorithm,
HashStrength = sslStream.HashStrength,
KeyExchangeAlgorithm = sslStream.KeyExchangeAlgorithm,
KeyExchangeStrength = sslStream.KeyExchangeStrength
};
}
