/// <inheritdoc />
public async Task <ITransport?> DoHandshakeAsync(CancellationToken cancellationToken = default)
{
cancellationToken.ThrowIfCancellationRequested();
_logger.LogDebug("Doing protocol handshake...");
ITransport currentTransport = _context.Transport ?? throw new InvalidOperationException("Cannot do handshake before a transport has been created.");
// Negotiate the protocol version that both sides will use
RfbProtocolVersion protocolVersion = await NegotiateProtocolVersionAsync(currentTransport, cancellationToken).ConfigureAwait(false);
_state.ProtocolVersion = protocolVersion;
// Negotiate which security type will be used
ISecurityType usedSecurityType = await NegotiateSecurityTypeAsync(currentTransport, cancellationToken).ConfigureAwait(false);
_state.UsedSecurityType = usedSecurityType;
// Execute authentication
_logger.LogDebug("Negotiated security type: {name}({id}). Authenticating...", usedSecurityType.Name, usedSecurityType.Id);
AuthenticationResult authenticationResult = await usedSecurityType
.AuthenticateAsync(_context.Connection.Parameters.AuthenticationHandler, cancellationToken).ConfigureAwait(false);
// When a tunnel was built, use that transport for further communication
if (authenticationResult.TunnelTransport != null)
{
currentTransport = authenticationResult.TunnelTransport;
}
if (authenticationResult.ExpectSecurityResult)
{
// Read the security result
ReadOnlyMemory <byte> securityResultBytes = await currentTransport.Stream.ReadAllAsync(4, cancellationToken).ConfigureAwait(false);
uint securityResult = BinaryPrimitives.ReadUInt32BigEndian(securityResultBytes.Span);
// Authentication failed?
if (securityResult > 0)
{
// From version 3.8 onwards the server sends a reason
if (protocolVersion >= RfbProtocolVersion.RFB_3_8)
{
string reason = await ReadFailureReasonAsync(currentTransport, cancellationToken).ConfigureAwait(false);
throw new HandshakeFailedException($"Authentication failed: {reason}");
}
// There is no reason
throw new HandshakeFailedException("Authentication failed" + (securityResult == 2 ? " because of too many attempts." : "."));
}
}
return(authenticationResult.TunnelTransport);
}
/// <inhertitdoc />
public async Task <TInput> ProvideAuthenticationInputAsync <TInput>(RfbConnection connection, ISecurityType securityType, IAuthenticationInputRequest <TInput> request)
where TInput : class, IAuthenticationInput
{
if (typeof(TInput) == typeof(PasswordAuthenticationInput))
{
string?password = await Dispatcher.UIThread.InvokeAsync(async() => await EnterPasswordInteraction.Handle(Unit.Default)).ConfigureAwait(false);
// TODO: Implement canceling of authentication input requests instead of passing an empty password!
if (password == null)
{
password = string.Empty;
}
return((TInput)Convert.ChangeType(new PasswordAuthenticationInput(password), typeof(TInput)));
}
throw new InvalidOperationException("The authentication input request is not supported by the interactive authentication handler.");
}