public static byte[] MessageTransmissionHandler(Message message)
{
byte[] textBytes = new byte[0];
if (!String.IsNullOrEmpty(message.Text))
{
textBytes = Encoding.Unicode.GetBytes(message.Text);
}
byte[] dataBytes = new byte[0];
if (message.Data != null)
{
dataBytes = message.Data;
}
byte[] messageBytes = ByteHelper.ConcatinateArray(BitConverter.GetBytes(message.From), new byte[] { (byte)message.Type });
messageBytes = ByteHelper.ConcatinateArray(messageBytes, dataBytes, textBytes);
return(messageBytes);
}
public static byte[] CreateNonMutualContactStatusMessage(int userId, bool relationshipTo, bool relationshipFrom)
{
UserObj user;
if (_users.Any(x => x.ID == userId))
{
user = _users.Find(x => x.ID == userId);
}
else
{
user = DatabaseCommunication.ReadUser(userId);
}
byte[] dataBytes;
dataBytes = ByteHelper.ConcatinateArray(BitConverter.GetBytes(user.ID), new byte[] { (byte)((relationshipTo ? 64 : 0) + (relationshipFrom ? 32 : 0) + user.Name.Length) }, Encoding.Unicode.GetBytes(user.Name));
return(dataBytes);
}
private static string CreateMac(byte[] messageBytes, string sharedSecret)
{
return(ByteHelper.GetHashString(ByteHelper.ConcatinateArray(ByteHelper.GetHashBytes(messageBytes), Convert.FromBase64String(sharedSecret))));
}
public static byte[] RemoveSignatureAndMac(byte[] bytes)
{
bytes = ByteHelper.SubArray(bytes, SignatureByteLength + ByteHelper.HashByteLength); // Remove the signature, the version number and the MAC.
return(bytes);
}
/// <summary>
/// This is a threaded method that keeps looping while _online is true.
/// It will receive UDP messages on the UdpClient's port number and forward them to the OnPacketReceived event.
/// </summary>
public void ReceivePacket() // Threaded looping method.
{
while (_online)
{
try
{
IPEndPoint remoteSender = new IPEndPoint(IPAddress.Any, 0);
byte[] receivedBytes = _client.Receive(ref remoteSender);
if (receivedBytes != null && receivedBytes.Length != 0)
{
if (receivedBytes.Length == ByteHelper.HashByteLength + 2 && receivedBytes[0] == 0xCE && receivedBytes[receivedBytes.Length - 1] == 0xCE)
{
if (_messageSendingControlList.Count != 0)
{
// The received message is a ACK message.
string hash = OpenAck(receivedBytes);
ControlledPacket packet = _messageSendingControlList.Find(x => x.Hash == hash);
if (packet != null)
{
_messageSendingControlList.Remove(packet);
}
}
}
else if (receivedBytes.Length == 1 && receivedBytes[0] == 0xEC)
{
// Fire an OnEtherConnectionReply event.
OnEtherConnectionReply(null);
}
else
{
// Send back an ACK packet.
string hash = ByteHelper.GetHashString(receivedBytes);
byte[] ackBytes = CreateAck(hash);
_client.Send(ackBytes, ackBytes.Length, remoteSender);
// Check if the message is a duplicate.
if (!_messageReceivingControlList.Any(x => x == hash))
{
// Add the message's hash to a list so we don't react on the same message twice.
_messageReceivingControlList.Add(hash);
if (_messageReceivingControlList.Count > 5) // Only keep the latest 5 messages.
{
_messageReceivingControlList.RemoveAt(0);
}
// Fire an OnPacketReceived event.
PacketReceivedEventArgs args = new PacketReceivedEventArgs();
args.Sender = remoteSender;
args.Data = receivedBytes;
OnPacketReceived(args);
}
}
}
}
catch (SocketException ex)
{
if (ex.SocketErrorCode != SocketError.TimedOut)
{
System.Diagnostics.Debug.WriteLine("### " + _threadPacketListener.Name + " has crashed:");
System.Diagnostics.Debug.WriteLine("### " + ex.Message);
System.Diagnostics.Debug.WriteLine("### " + ex.ToString());
break;
}
else
{
continue;
}
}
}
}
/// <summary>
/// Create an ACK packet from a base64 hash string.
/// </summary>
/// <param name="hash">Base64 hash string to be used.</param>
protected byte[] CreateAck(string hash)
{
byte[] ackTag = new byte[] { 0xCE }; // 0xCE = 206
byte[] ackBytes = ByteHelper.ConcatinateArray(ackTag, Convert.FromBase64String(hash), ackTag);
return(ackBytes);
}
public static void SendAllContacts(int userId)
{
Dictionary <int, byte> contacts = DatabaseCommunication.GetAllContacts(userId);
foreach (KeyValuePair <int, byte> contact in contacts)
{
byte[] contactStatusMessageBytes;
if (contact.Value == 0x03) // 0b00000011
{
contactStatusMessageBytes = CreateMutualContactStatusMessage(contact.Key);
}
else
{
contactStatusMessageBytes = CreateNonMutualContactStatusMessage(contact.Key, ByteHelper.CheckBitCodeIndex(contact.Value, 0), ByteHelper.CheckBitCodeIndex(contact.Value, 1));
}
MessageToUser(userId, ChatTwo_Protocol.MessageType.ContactStatus, contactStatusMessageBytes);
}
}
public static void MessageReceivedHandler(object sender, PacketReceivedEventArgs args)
{
if (!DatabaseCommunication.Active)
#if DEBUG
{ throw new NotImplementedException("Database connection was not active and a reply for this have not been implemented yet."); }
// Need to add a simple debug message here, but this works as a great breakpoint until then.
// Also need to make some kind of error message I can send back to the client.
#else
{ return; }
#endif
if (args.Data[0] == 0x92)
{
string sharedSecret;
// Position of the Type byte is 30 (SignatureByteLength + MacByteLength + TimezByteLength + UserIdByteLength).
ChatTwo_Protocol.MessageType type = (ChatTwo_Protocol.MessageType)args.Data[ChatTwo_Protocol.SignatureByteLength + ByteHelper.HashByteLength + 4 + 4];
// Position of the UserID bytes is 26 (SignatureByteLength + MacByteLength + TimezByteLength) with a length of 4.
int userId = ByteHelper.ToInt32(args.Data, ChatTwo_Protocol.SignatureByteLength + ByteHelper.HashByteLength + 4);
if (type == ChatTwo_Protocol.MessageType.CreateUser)
{
sharedSecret = ChatTwo_Protocol.DefaultSharedSecret;
}
else if (type == ChatTwo_Protocol.MessageType.Login)
{
#if DEBUG
byte[] test = ByteHelper.SubArray(args.Data, ChatTwo_Protocol.SignatureByteLength + ByteHelper.HashByteLength + 4);
#endif
// Don't take the Timez as part of the sharedSecret. This is mostly because of a problem I have in the client where I make the sharedSecrt before I add the Timez.
sharedSecret = ByteHelper.GetHashString(ByteHelper.SubArray(args.Data, ChatTwo_Protocol.SignatureByteLength + ByteHelper.HashByteLength + 4));
}
else
{
if (!_users.Any(x => x.ID == userId))
{
return; // This is mostly to prevent clients with a connection to a previces server instants from crashing the server. Need to fix this.
}
sharedSecret = _users.Find(x => x.ID == userId).Secret;
}
if (ChatTwo_Protocol.ValidateMac(args.Data, sharedSecret))
{
Message message = ChatTwo_Protocol.MessageReceivedHandler(args);
switch (message.Type)
{
case ChatTwo_Protocol.MessageType.CreateUser:
{
string passwordHash = Convert.ToBase64String(message.Data, 0, ByteHelper.HashByteLength);
string username = Encoding.Unicode.GetString(ByteHelper.SubArray(message.Data, ByteHelper.HashByteLength));
if (username.Length < 1 || username.Length > 30)
{
// Username is too short or too long.
MessageToIp(message.Ip, ChatTwo_Protocol.MessageType.CreateUserReply, new byte[] { 0x02 });
return;
}
bool worked = DatabaseCommunication.CreateUser(username, passwordHash);
if (!worked)
{
// Some error prevented the user from being created. Best guess is that a user with that name already exist.
MessageToIp(message.Ip, ChatTwo_Protocol.MessageType.CreateUserReply, new byte[] { 0x01 });
return;
}
// Uesr creation was successful!
MessageToIp(message.Ip, ChatTwo_Protocol.MessageType.CreateUserReply, new byte[] { 0x00 });
break;
}
case ChatTwo_Protocol.MessageType.Login:
{
string passwordHash = Convert.ToBase64String(message.Data, 0, ByteHelper.HashByteLength);
string username = Encoding.Unicode.GetString(ByteHelper.SubArray(message.Data, ByteHelper.HashByteLength));
UserObj user = DatabaseCommunication.LoginUser(username, passwordHash);
if (user == null)
{
// Have to send back a LoginReply message here with a "wrong username/password" error.
_tempUsers.Add(message.Ip, sharedSecret);
MessageToIp(message.Ip, ChatTwo_Protocol.MessageType.LoginReply, new byte[] { 0x01 });
return;
}
if (_users.Any(x => x.ID == user.ID))
{
// Have to send back a LoginReply message here with a "User is already online" error.
_tempUsers.Add(message.Ip, sharedSecret);
MessageToIp(message.Ip, ChatTwo_Protocol.MessageType.LoginReply, new byte[] { 0x02 });
return;
}
user.Secret = sharedSecret;
user.Socket = message.Ip;
user.Online = true;
_users.Add(user);
MessageToUser(user.ID, ChatTwo_Protocol.MessageType.LoginReply, ByteHelper.ConcatinateArray(new byte[] { 0x00 }, BitConverter.GetBytes(user.ID)), user.Name);
UserConnect(user);
break;
}
case ChatTwo_Protocol.MessageType.Status:
{
UserObj user = _users.Find(x => x.ID == message.From);
if (user != null) // If the user is not found, don't do anything. (Can this happen?)
{
if (!IPEndPoint.Equals(user.Socket, message.Ip))
{
user.Socket = message.Ip;
// Message all contacts of the user with the new IP change.
TellMutualContactsAboutUserStatusChange(user.ID);
}
DatabaseCommunication.UpdateUser(user.ID, user.Socket);
}
break;
}
case ChatTwo_Protocol.MessageType.ContactRequest:
{
string username = Encoding.Unicode.GetString(message.Data);
UserObj user = DatabaseCommunication.LookupUser(username);
if (user == null)
{
// Have to send back a ContactRequestReply message here with a "No user with that name" error.
MessageToUser(message.From, ChatTwo_Protocol.MessageType.ContactRequestReply, new byte[] { 0x01 });
return;
}
if (user.ID == message.From)
{
// Have to send back a ContactRequestReply message here with a "You can't add your self" error.
MessageToUser(message.From, ChatTwo_Protocol.MessageType.ContactRequestReply, new byte[] { 0x02 });
return;
}
bool added = DatabaseCommunication.AddContact(message.From, user.ID);
if (!added)
{
// Have to send back a ContactRequestReply message here with a "User is already a contact" error.
MessageToUser(message.From, ChatTwo_Protocol.MessageType.ContactRequestReply, new byte[] { 0x03 });
return;
}
MessageToUser(message.From, ChatTwo_Protocol.MessageType.ContactRequestReply, new byte[] { 0x00 });
//if (_users.Any(x => x.ID == user.ID))
// TellContactsAboutUserStatusChange(message.From, true); // Need to figure this out.
break;
}
}
}
#if DEBUG
else
{
throw new NotImplementedException("Could not validate the MAC of the received message.");
}
// Need to add a simple debug message here, but this works as a great breakpoint until then.
#endif
}
#if DEBUG
else
{
throw new NotImplementedException("Could not validate the signature of the received message. The signature was \"0x" + args.Data[0] + "\" but only \"0x92\" is allowed.");
}
// Need to add a simple debug message here, but this works as a great breakpoint until then.
#endif
}