/// <summary>
/// Extension method:
/// Casts the <see cref="IWcfLogger"/> object to the type specified by <typeparamref name="T"/>.
/// </summary>
/// <typeparam name="T">The type to wich the object needs to be casted.</typeparam>
/// <param name="obj">The object to cast.</param>
/// <returns>The casted object if succeed, null otherwise.</returns>
public static T Cast <T>(this IWcfLogger obj) where T : class
{
return(obj as T);
}
/// <summary>
/// Process the logged messages sending them to the server.
/// </summary>
private static void ProcessMessages()
{
HMACSHA256 hmacCalculator = null;
//run indefinetly
while (true)
{
//try to connect
IWcfLogger channel = s_Factory.CreateChannel();
TimeSpan timeout = new TimeSpan(0, 1, 0);
while (channel.Cast <ICommunicationObject>().State != CommunicationState.Opened)
{
try
{
channel.Cast <ICommunicationObject>().Open(timeout);
//perform handshake
BigInteger mod = IWcfLoggerUtility.GenerateRandomInt();
BigInteger prKey = IWcfLoggerUtility.GenerateRandomInt();
LogInReply reply = channel.LogIn(mod, IWcfLoggerUtility.GetPublicKey(2, mod, prKey), "admin");
if (reply.Status)
{
BigInteger sharedKey = IWcfLoggerUtility.GetSharedKey(mod, prKey, reply.PublicKey);
//check the password
SHA256 hasher = SHA256.Create();
byte[] tmp = hasher.ComputeHash(Encoding.UTF8.GetBytes("password").Concat(mod.ToByteArray()).ToArray());
tmp = hasher.ComputeHash(tmp.Concat(sharedKey.ToByteArray()).ToArray());
if (tmp.SequenceEqual(reply.PasswordToken.ToByteArray()))
{
hmacCalculator = new HMACSHA256(sharedKey.ToByteArray());
//exit the loop
break;
}
}
channel.Cast <ICommunicationObject>().Abort();
}
catch
{
//re-create the channel and try again
channel.Cast <ICommunicationObject>().Abort();
channel = s_Factory.CreateChannel();
}
}
//now channel is open, start sending messages
while (channel.Cast <ICommunicationObject>().State == CommunicationState.Opened)
{
List <LogMessage> toSend = new List <LogMessage>();
//check for messages
s_MsgAvaialble.WaitOne();
lock (s_Lock)
{
toSend = s_MsgQueue.ToList();
s_MsgQueue.Clear();
}
foreach (LogMessage msg in toSend)
{
//get byte array associated with the message
byte[] data = BitConverter.GetBytes(msg.Id)
.Concat(BitConverter.GetBytes(msg.Date.ToBinary()))
.Concat(Encoding.UTF8.GetBytes(msg.Caller))
.Concat(Encoding.UTF8.GetBytes(msg.Message))
.ToArray();
//compute HMAC and send message
channel.SendMessage(msg, new BigInteger(hmacCalculator.ComputeHash(data)));
}
}
}
}
