/// <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>
/// <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)
{
return Connect(hostname, port, credential, sslSupportMode, userValidateServerCertificate, x509ClientCert,
sslMinKeyExchangeAlgStrength, sslMinCipherAlgStrength, sslMinHashAlgStrength, timeout, true, EDataConnectionMode.Passive);
}
/// <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)
_timeout = timeout.Value;
_sslClientCert = x509ClientCert;
_userValidateServerCertificate = userValidateServerCertificate;
_sslMinKeyExchangeAlgStrength = sslMinKeyExchangeAlgStrength;
_sslMinCipherAlgStrength = sslMinCipherAlgStrength;
_sslMinHashAlgStrength = sslMinHashAlgStrength;
_sslSupportRequestedMode = sslSupportMode;
_sslSupportCurrentMode = sslSupportMode;
_useCtrlEndPointAddressForData = useCtrlEndPointAddressForData;
_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
_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;
}
public string Connect(string hostname, int port, NetworkCredential credential, EsslSupportMode sslSupportMode, int? timeout)
{
return Connect(hostname, port, credential, sslSupportMode, null, null, 0, 0, 0, timeout);
}
public string Connect(string hostname, NetworkCredential credential, EsslSupportMode sslSupportMode,
RemoteCertificateValidationCallback userValidateServerCertificate)
{
// Default implicit FTPS port is 990, default standard and explicit FTPS port is 21
int port = (sslSupportMode & EsslSupportMode.Implicit) == EsslSupportMode.Implicit ? 990 : 21;
return Connect(hostname, port, credential, sslSupportMode, userValidateServerCertificate, null, 0, 0, 0, null);
}
public string Connect(string hostname, NetworkCredential credential, EsslSupportMode sslSupportMode)
{
return Connect(hostname, credential, sslSupportMode, null);
}
/// <summary>
/// Anonymous authentication
/// </summary>
/// <param name="hostname"></param>
/// <returns>The text of the \"welcome message\" sent by the server.</returns>
public string Connect(string hostname, EsslSupportMode sslSupportMode)
{
return Connect(hostname, null, sslSupportMode);
}
private void SslDataChannelCheckExplicitEncryptionRequest()
{
if ((_sslSupportCurrentMode & EsslSupportMode.DataChannelRequested) == EsslSupportMode.DataChannelRequested) {
PbszCmd(0);
try {
ProtCmd(EProtCode.P);
} catch (FtpCommandException ex) {
// Note: MS FTP 7.0 returns 536, but RFC 2228 requires 534
if ((_sslSupportCurrentMode & EsslSupportMode.DataChannelRequired) == EsslSupportMode.DataChannelRequired)
if (ex.ErrorCode == 534 || ex.ErrorCode == 536)
throw new FtpSslException("The server policy denies SSL/TLS", ex);
else
throw;
_sslSupportCurrentMode ^= EsslSupportMode.DataChannelRequired;
// Data channel transfers will be done in clear text
ProtCmd(EProtCode.C);
}
}
}
private void SSlCtrlChannelCheckRevertToClearText()
{
// Back to clear text mode, but only if supported by the server
if (CheckFeature("CCC"))
CccCmd();
else
_sslSupportCurrentMode |= EsslSupportMode.ControlChannelRequested;
}
private void SslControlChannelCheckExplicitEncryptionRequest(EsslSupportMode sslSupportMode)
{
if ((sslSupportMode & EsslSupportMode.CredentialsRequested) == EsslSupportMode.CredentialsRequested)
try {
AuthCmd(EAuthMechanism.Tls);
} catch (FtpCommandException ex) {
if ((sslSupportMode & EsslSupportMode.CredentialsRequired) == EsslSupportMode.CredentialsRequired)
if (ex.ErrorCode == 530 || ex.ErrorCode == 534)
throw new FtpSslException("SSL/TLS connection not supported on server", ex);
else
throw;
_sslSupportCurrentMode = EsslSupportMode.ClearText;
}
}
