/// <summary>
/// Connect to a VNC Host and determine which type of Authentication it uses. If the host uses Password Authentication, a call to Authenticate() will be required.
/// </summary>
/// <param name="host">The IP Address or Host Name of the VNC Host.</param>
/// <param name="display">The Display number (used on Unix hosts).</param>
/// <param name="port">The Port number used by the Host, usually 5900.</param>
/// <param name="viewOnly">True if mouse/keyboard events are to be ignored.</param>
/// <returns>Returns True if the VNC Host requires a Password to be sent after Connect() is called, otherwise False.</returns>
public bool Connect(string host, int display, int port, bool viewOnly)
{
if (host == null) throw new ArgumentNullException("host");
// If a diplay number is specified (used to connect to Unix servers)
// it must be 0 or greater. This gets added to the default port number
// in order to determine where the server will be listening for connections.
if (display < 0) throw new ArgumentOutOfRangeException("display", display, "Display number must be non-negative.");
port += display;
rfb = new RfbProtocol();
if (viewOnly) {
inputPolicy = new VncViewInputPolicy(rfb);
} else {
inputPolicy = new VncDefaultInputPolicy(rfb);
}
// Connect and determine version of server, and set client protocol version to match
try {
rfb.Connect(host, port);
rfb.ReadProtocolVersion();
rfb.WriteProtocolVersion();
// Figure out which type of authentication the server uses
byte[] types = rfb.ReadSecurityTypes();
// Based on what the server sends back in the way of supported Security Types, one of
// two things will need to be done: either the server will reject the connection (i.e., type = 0),
// or a list of supported types will be sent, of which we need to choose and use one.
if (types.Length > 0) {
if (types[0] == 0) {
// The server is not able (or willing) to accept the connection.
// A message follows indicating why the connection was dropped.
throw new VncProtocolException("Connection Failed. The server rejected the connection for the following reason: " + rfb.ReadSecurityFailureReason());
} else {
securityType = GetSupportedSecurityType(types);
Debug.Assert(securityType > 0, "Unknown Security Type(s)", "The server sent one or more unknown Security Types.");
rfb.WriteSecurityType(securityType);
// Protocol 3.8 states that a SecurityResult is still sent when using NONE (see 6.2.1)
if (rfb.ServerVersion == 3.8f && securityType == 1) {
if (rfb.ReadSecurityResult() > 0) {
// For some reason, the server is not accepting the connection. Get the
// reason and throw an exception
throw new VncProtocolException("Unable to Connecto to the Server. The Server rejected the connection for the following reason: " + rfb.ReadSecurityFailureReason());
}
}
return (securityType > 1) ? true : false;
}
} else {
// Something is wrong, since we should have gotten at least 1 Security Type
throw new VncProtocolException("Protocol Error Connecting to Server. The Server didn't send any Security Types during the initial handshake.");
}
} catch (Exception e) {
throw new VncProtocolException("Unable to connect to the server. Error was: " + e.Message, e);
}
}
/// <summary>
/// Connect to a VNC Host and determine which type of Authentication it uses. If the host uses Password Authentication,
/// a call to Authenticate() will be required.
/// </summary>
/// <param name="host">The IP Address or Host Name of the VNC Host.</param>
/// <param name="display">The Display number (used on Unix hosts).</param>
/// <param name="port">The Port number used by the Host, usually 5900.</param>
/// <param name="viewOnly">True if mouse/keyboard events are to be ignored.</param>
/// <returns>Returns True if the VNC Host requires a Password to be sent after Connect() is called, otherwise False.</returns>
public bool Connect(string host, int display, int port, bool viewOnly)
{
if (host == null)
{
throw new ArgumentNullException(nameof(host));
}
// If a diplay number is specified (used to connect to Unix servers)
// it must be 0 or greater. This gets added to the default port number
// in order to determine where the server will be listening for connections.
if (display < 0)
{
throw new ArgumentOutOfRangeException(nameof(display), display, "Display number must be non-negative.");
}
port += display;
rfb = new RfbProtocol();
viewOnlyMode = viewOnly;
if (viewOnly)
{
inputPolicy = new VncViewInputPolicy(rfb);
}
else
{
inputPolicy = new VncDefaultInputPolicy(rfb);
}
// Connect and determine version of server, and set client protocol version to match
try
{
rfb.Connect(host, port);
rfb.ReadProtocolVersion();
// Handle possible repeater connection
if (rfb.ServerVersion == 0.0)
{
rfb.WriteProxyAddress();
// Now we are connected to the real server; read the protocol version of the
// server
rfb.ReadProtocolVersion();
// Resume normal handshake and protocol
}
rfb.WriteProtocolVersion();
// Figure out which type of authentication the server uses
var types = rfb.ReadSecurityTypes();
// Based on what the server sends back in the way of supported Security Types, one of
// two things will need to be done: either the server will reject the connection (i.e., type = 0),
// or a list of supported types will be sent, of which we need to choose and use one.
if (types.Length <= 0)
{
// Something is wrong, since we should have gotten at least 1 Security Type
throw new VncProtocolException(
"Protocol Error Connecting to Server. The Server didn't send any Security Types during the initial handshake.");
}
if (types[0] == 0)
{
// The server is not able (or willing) to accept the connection.
// A message follows indicating why the connection was dropped.
throw new VncProtocolException(
"Connection Failed. The server rejected the connection for the following reason: " +
rfb.ReadSecurityFailureReason());
}
securityType = GetSupportedSecurityType(types);
Debug.Assert(securityType > 0, "Unknown Security Type(s)",
"The server sent one or more unknown Security Types.");
rfb.WriteSecurityType(securityType);
// Protocol 3.8 states that a SecurityResult is still sent when using NONE (see 6.2.1)
if (rfb.ServerVersion != 3.8f || securityType != 1)
{
return(securityType > 1);
}
if (rfb.ReadSecurityResult() > 0)
{
// For some reason, the server is not accepting the connection. Get the
// reason and throw an exception
throw new VncProtocolException(
"Unable to Connecto to the Server. The Server rejected the connection for the following reason: " +
rfb.ReadSecurityFailureReason());
}
return(securityType > 1);
}
catch (Exception e)
{
throw new VncProtocolException("Unable to connect to the server. Error was: " + e.Message, e);
}
}