internal static void RegisterClient(Client c)
{
Clients[c.u] = c;
}
internal static void UnRegisterClient(Client user)
{
if (!Clients.ContainsKey(user.u)) return;
Clients.Remove(user.u);
}
/// <summary>
/// Handles a newly accepted TCP client from the listener
/// </summary>
/// <param name="c">The client to handle</param>
internal static void HandleClient(TcpClient c)
{
var rep = c.Client.RemoteEndPoint;
try {
// Get a networkstream to work with
var s = c.GetStream();
// Initialize a new RSA class to exchange the symetrical keys
var rsa = new RSACryptoServiceProvider();
// Get the RSA public key from the client
var pk = GetPublicKey(s);
// If the public key was null (e.g. the stream closed), toss out this client
if (pk == null) {
return;
}
// If the key wasn't null, import it as the new key for the RSA class
rsa.ImportCspBlob(pk);
// Generate a new AES provider with a 256-bit key
var aes = new AesCryptoServiceProvider {KeySize = 256};
// Generate the Key and Initialization vector
aes.GenerateKey();
aes.GenerateIV();
// Encrypt the AES Key and IV for transportation to the client
var aeskey = Encryption.RSAEncrypt(aes.Key, rsa.ExportParameters(false), false);
var aesiv = Encryption.RSAEncrypt(aes.IV, rsa.ExportParameters(false), false);
// Write the key and iv to the stream
s.Write(new[] {(byte) aeskey.Length}, 0, 1);
s.Write(aeskey, 0, aeskey.Length);
s.Write(new[] {(byte) aesiv.Length}, 0, 1);
s.Write(aesiv, 0, aesiv.Length);
// Read the username and password from the client
var r = new byte[4096];
var br = s.Read(r, 0, 4096);
if (br == 0) return;
var userpass = Encryption.DecryptStringFromBytesAes(r, br, aes.Key, aes.IV, e);
// Split the data in two at the first colon to seperate username from password
var userpass_ = userpass.Split(new[]{':'}, 2);
// Turn the username and password into their own variables
var user = userpass_[0];
var pass = userpass_[1];
// Attempt to authenticate the user
var uar = Authentication.Authenticate(user, pass);
// If the authentication wasn't successful...
if (uar != UserAuthResult.Success) {
if (uar == UserAuthResult.Banned) {
// If the user was banned, tell them they are banned
var banm = Encryption.EncryptStringToBytesAes("USER_BANNED", aes.Key, aes.IV, e);
s.Write(banm, 0, banm.Length);
} else {
// If the user does not exist or the password was wrong, tell them they had bad credentials
var buop = Encryption.EncryptStringToBytesAes("BAD_CRED", aes.Key, aes.IV, e);
s.Write(buop, 0, buop.Length);
}
// Finally, send the client packing
c.Close();
return;
}
var smes = Encryption.EncryptStringToBytesAes("IM_OLD_GREGG__PLEASED_TO_MEET_YA", aes.Key, aes.IV, e);
s.Write(smes, 0, smes.Length);
Console.WriteLine("{0} authenticated successfully as {1}", rep, user);
// Pass the client on to the sustainable client class
var h = new Client(c, user, aes);
h.Start();
}
catch (Exception exception) {
// If there was an IO exception, write it to the console
Console.WriteLine("Exception occured in client handler.\nClient: {1}\nDetails: {0}\n{2}",
exception.GetType(), rep, exception.Message);
if (c.Connected) c.Close();
}
}
