// Communication
private void TrySend(byte[] buffer, bool doEncryption)
{
byte[] b = buffer;
if (doEncryption && serverEncryptor != null)
{
b = serverEncryptor.AESEncryptBytes(buffer);
}
WriteResult result = client.SendWithTimeout(maxPingMs, b);
if (result.Status != WriteResultStatus.Success)
{
throw new FailedSendingException($"Could not send data ({result.Status}).");
}
}
private async Task EstablishConnection()
{
await Task.Run(() =>
{
CommunicationResult res = null;
byte[] buffer = null;
// Deny, accept, or askpass
res = TryRead(1, maxPingMs + Settings.SettingsData.MaxPermissionAskWaitMs);
// Denied
switch (res.Instruction)
{
case TTInstruction.Connection_RefuseBusy:
throw new FailedConnectingException($"Connection to {serverDevice.Name} failed because it's busy right now.");
case TTInstruction.Connection_RefuseDeny:
throw new FailedConnectingException($"Connection to {serverDevice.Name} failed because it hasn't allowed you to send them files.");
}
// Encryption
DataEncryptor encryptor = null;
if (serverDevice.EncryptionEnabled)
{
// Check if server also has password set
if (res.Instruction != TTInstruction.Connection_AskPass)
{
TrySend(new byte[] { (byte)TTInstruction.Connection_RefusePass }, false);
throw new FailedConnectingException($"Connection to {serverDevice.Name} refused because you have set a password and it has none.");
}
// Send password
encryptor = new DataEncryptor(serverDevice.EncryptionPassword);
byte[] timePassword = TTNet.GenerateTimePasswordBytes();
buffer = new byte[1] {
(byte)TTInstruction.Connection_SendPass
}.ToList().Concat(encryptor.AESEncryptBytes(timePassword)).ToArray();
TrySend(buffer, false);
// Receive password response
res = TryRead(1);
if (res.Instruction != TTInstruction.Connection_AcceptPass)
{
throw new FailedConnectingException($"Connection to {serverDevice.Name} failed because you do not have the right password.");
}
// Receive password
try
{
res = TryRead(TTNet.TimePasswordLength + 1);
}
catch (Exception e)
{
OnRecordableEvent("Caught " + e.Message, Console.ConsoleMessageType.Error);
throw new Exception();
}
// Check password
byte[] receivedTimePassword = encryptor.AESDecryptBytes(res.Data);
if (Enumerable.SequenceEqual(timePassword, receivedTimePassword) || !TTNet.CheckTimePasswordValid(receivedTimePassword, serverDevice, maxPingMs))
{
// TODO Send RefusePass to server
throw new FailedConnectingException($"Connection to {serverDevice.Name} refused because it did not have the correct password.");
}
}
else
{
// Check if server also doesn't use password
if (res.Instruction != TTInstruction.Connection_Accept)
{
TrySend(new byte[] { (byte)TTInstruction.Connection_RefuseDeny }, false); // TODO Doesn't work, server doesn't recognize this scenario
throw new FailedConnectingException($"Connection to {serverDevice.Name} failed because it requires a password and none is set.");
}
}
// Send connection accept
TrySend(new byte[] { (byte)TTInstruction.Connection_Accept }, false);
serverEncryptor = encryptor;
OnRecordableEvent($"Established { (serverDevice.EncryptionEnabled ? "secure " : "")}connection with {serverDevice.Name}.", Console.ConsoleMessageType.Common);
});
}
private async Task EstablishConnection(string ipPort)
{
await Task.Run(() =>
{
if (ipPort == null || ipPort == "")
{
throw new FailedConnectingException("Wrong IP.");
}
string[] ipParts = ipPort.Split(':');
if (ipParts.Length != 2)
{
throw new FailedConnectingException("Wrong IP.");
}
IPAddress deviceIP;
if (!IPAddress.TryParse(ipParts[0], out deviceIP))
{
throw new FailedConnectingException("Unknown IP.");
}
Device remoteDevice = Settings.SettingsData.GetDevice(deviceIP);
if (remoteDevice == null)
{
throw new FailedConnectingException("Unknown IP.");
}
CommunicationResult res = null;
byte[] buffer = null;
// Check busy
if (IsBusy)
{
TrySend(ipPort, new byte[] { (byte)TTInstruction.Connection_RefuseBusy });
throw new FailedConnectingException($"Connection from {remoteDevice.Name} refused because busy.");
}
// Check permission
if (remoteDevice.ReceiveMode == DeviceReceiveMode.Deny)
{
TrySend(ipPort, new byte[] { (byte)TTInstruction.Connection_RefuseDeny });
throw new FailedConnectingException($"Connection from {remoteDevice.Name} refused because it's not allowed.");
}
if (remoteDevice.ReceiveMode == DeviceReceiveMode.AskEachTime)
{
timer = new Timer(Settings.SettingsData.MaxPermissionAskWaitMs);
timer.Elapsed += Events_TimerPermissionAskTimeout;
timer.Start();
bool allowed = false;
Application.Current.Dispatcher.Invoke(() =>
{
confirmationDialog = new Settings.ConfirmationDialog("Accept connection?", $"Do you want to accept a connection from '{remoteDevice.Name}'?", "Yes", "No");
confirmationDialog.Owner = Application.Current.MainWindow;
allowed = confirmationDialog.ShowDialog() ?? false;
});
timer.Stop();
timer.Dispose();
if (!allowed)
{
timer.Stop();
timer.Dispose();
TrySend(ipPort, new byte[] { (byte)TTInstruction.Connection_RefuseDeny });
throw new FailedConnectingException($"Connection from {remoteDevice.Name} refused because you refused it.");
}
}
// Encryption
DataEncryptor encryptor = null;
if (remoteDevice.EncryptionEnabled)
{
encryptor = new DataEncryptor(remoteDevice.EncryptionPassword);
// Ask for password
TrySend(ipPort, new byte[] { (byte)TTInstruction.Connection_AskPass });
// Receive password
res = TryRead(ipPort, 1 + TTNet.TimePasswordLength, false);
if (res.Instruction != TTInstruction.Connection_SendPass)
{
if (res.Instruction == TTInstruction.Connection_RefuseDeny)
{
throw new FailedConnectingException($"Connection from {remoteDevice.Name} refused refused because it did not have a password.");
}
}
// Check password
byte[] receivedTimePassword = encryptor.AESDecryptBytes(res.Data);
if (!TTNet.CheckTimePasswordValid(receivedTimePassword, remoteDevice, maxPingMs))
{
TrySend(ipPort, new byte[] { (byte)TTInstruction.Connection_RefusePass });
throw new FailedConnectingException($"Connection from {remoteDevice.Name} refused because it did not have the correct password.");
}
TrySend(ipPort, new byte[] { (byte)TTInstruction.Connection_AcceptPass });
// Send password
byte[] timePassword = TTNet.GenerateTimePasswordBytes();
buffer = new byte[1] {
(byte)TTInstruction.Connection_SendPass
}.ToList().Concat(encryptor.AESEncryptBytes(timePassword)).ToArray();
TrySend(ipPort, buffer);
}
else
{
// Send connection accept
TrySend(ipPort, new byte[] { (byte)TTInstruction.Connection_Accept });
}
// Wait if client accepted connection
res = TryRead(ipPort, 1, false);
if (res.Instruction != TTInstruction.Connection_Accept)
{
if (res.Instruction == TTInstruction.Connection_RefusePass)
{
throw new FailedConnectingException($"Connection from {remoteDevice.Name} refused because it requires a password and none is set.");
}
}
// Check busy again
if (IsBusy)
{
TrySend(ipPort, new byte[] { (byte)TTInstruction.Connection_RefuseBusy });
throw new FailedConnectingException($"Refused connection from {remoteDevice.Name} because busy.");
}
clientDevice = remoteDevice;
clientIpPort = ipPort;
clientEncryptor = encryptor;
OnRecordableEvent($"Established { (clientDevice.EncryptionEnabled ? "secure " : "")}connection with {remoteDevice.Name}.", Console.ConsoleMessageType.Common);
});
}