/// <summary>
/// Processes a raw command packet that has been received and identified as being
/// sent to this connection.
/// </summary>
/// <param name="command_packet">Command packet data</param>
public void ProcessCommandPacket(string command_packet)
{
try
{
int pcmd = 0;
Command new_cmd = new Command();
new_cmd.OPCode = command_packet.Substring(pcmd, 2);
pcmd += 2;
new_cmd.SequenceNum = Util.BytesToUint(command_packet.Substring(pcmd, 4));
pcmd += 4;
new_cmd.Flags = (byte)command_packet[pcmd];
pcmd++;
new_cmd.NumFields = Util.BytesToShort(command_packet.Substring(pcmd, 2));
pcmd += 2;
new_cmd.FieldSizes = new short[new_cmd.NumFields];
for (short i = 0; i < new_cmd.NumFields; i++)
{
new_cmd.FieldSizes[i] = Util.BytesToShort(command_packet.Substring(pcmd, 2));
pcmd += 2;
}
//Is a reliable packet? Send an acknowledgement back
if ((new_cmd.Flags & UdpConsts.FLAGS_RELIABLE) > 0)
{
m_Parent.DebugDump("Got a reliable packet (" + new_cmd.SequenceNum.ToString() + ") - sent acknowledgement to sender.");
SendUnreliableCommand(0, UdpConsts.OPCODE_RELIABLEACK, new string[] { new_cmd.SequenceNum.ToString() });
//Repeat reliable packet - sender must not have received our acknowledgement
if (LastReceivedPacketR == new_cmd.SequenceNum)
{
m_Parent.DebugDump("Repeated reliable packet - not processed.");
return;
}
//Update last received reliable command number
LastReceivedPacketR = new_cmd.SequenceNum;
}
else
{
LastReceivedPacket = new_cmd.SequenceNum; //Update unreliable command number
if ((new_cmd.Flags & UdpConsts.FLAGS_SEQUENCED) > 0)
{
//If this sequenced packet has arrived too late (a newer one got there first) then don't process it
if (LastReceivedPacketSeq > new_cmd.SequenceNum)
{
m_Parent.DebugDump("Unreliable sequenced packet arrived out of order - ignored.");
return;
}
//Update the last sequenced packet number if we should
LastReceivedPacketSeq = new_cmd.SequenceNum;
}
}
//Encryption check
if ((new_cmd.Flags & UdpConsts.FLAGS_ENCRYPTED) > 0)
{
if (EncryptionKey != "")
if (Util.XORCrypt(command_packet.Substring(pcmd, 2), EncryptionKey) != UdpConsts.ENCRYPT_CHECK_STRING)
{
//!!BAD ENCRYPTION KEY
m_Parent.DebugDump("Received an encrypted packet but the stored encryption key failed to decrypt it!");
return;
}
}
pcmd += 2;
//Populate the AllFields property of the command
new_cmd.AllFields = command_packet.Substring(pcmd);
if ((new_cmd.Flags & UdpConsts.FLAGS_RELIABLE) > 0)
{
//Is this reliable packet a compound piece?
if ((new_cmd.Flags & UdpConsts.FLAGS_COMPOUNDPIECE) > 0)
{
//Assume this is the first piece of the split command
if (CompoundCommand == null)
{
m_Parent.DebugDump("Got first part of a compound command, stored.");
CompoundCommand = new Command();
CompoundCommand.AllFields = new_cmd.AllFields;
CompoundCommand.FieldSizes = new_cmd.FieldSizes;
CompoundCommand.Flags = new_cmd.Flags;
//Remove the compound piece flag (will be treated as a single packet)
CompoundCommand.Flags &= (byte)(~UdpConsts.FLAGS_COMPOUNDPIECE);
CompoundCommand.NumFields = new_cmd.NumFields;
CompoundCommand.SequenceNum = new_cmd.SequenceNum;
CompoundCommand.OPCode = new_cmd.OPCode;
return;
}
else
{
//Additional pieces have FLAGS_COMPOUNDPIECE set also....
m_Parent.DebugDump("Got an additional compound piece.");
//Is not the first nor last part so just addon the fields
CompoundCommand.AllFields += new_cmd.AllFields;
return;
}
}
//The last compound piece has FLAGS_COMPOUNDEND set.
if ((new_cmd.Flags & UdpConsts.FLAGS_COMPOUNDEND) > 0)
{
m_Parent.DebugDump("Got last compound piece - sending to command processing.");
//Add the fields on
CompoundCommand.AllFields += new_cmd.AllFields;
//Swap the incomplete part with the whole command
new_cmd = CompoundCommand;
CompoundCommand = null;
}
}
new_cmd.Initialize();
//If the packet is encrypted decrypt the fields now...
if ((new_cmd.Flags & UdpConsts.FLAGS_ENCRYPTED) > 0)
{
new_cmd.AllFields = "";
//Decrypt the fields
for (int i = 0; i < new_cmd.NumFields; i++)
{
new_cmd.Fields[i] = Util.XORCrypt(new_cmd.Fields[i], EncryptionKey);
//Rebuild the allfields property with the decrypted field data
new_cmd.AllFields += new_cmd.Fields[i];
}
}
//Send to command processing
ProcessCompletedCommand(new_cmd);
}
catch
{
m_Parent.DebugDump("Exception whilst parsing input from " + RemoteEP.ToString() + " as command, probably not a command. Ignoring.");
}
}
/// <summary>
/// This function is called internally when a command has been parsed and is ready to be processed
/// by the UDP engine and possibly the host application.
/// </summary>
/// <param name="cmd">Object containing data about the command to be processed.</param>
public void ProcessCompletedCommand(Command cmd)
{
//Client sent login details
if (!Authed)
{
if (cmd.OPCode == UdpConsts.OPCODE_LOGINDETAILS)
{
m_Parent.ConnectionAuthing(this, cmd);
return;
}
}
//Remote host sent us a ping
if (cmd.OPCode == UdpConsts.OPCODE_PING)
{
if(Authed)
{
m_Parent.DebugDump("Received ping from " + this.RemoteEP.ToString());
UpdateTimeout();
if (!Server) //If this is not a connection to a server
SendUnreliableCommand(0, UdpConsts.OPCODE_PING, null);
}
return;
}
//Server sent acknowledgement of our connection
if (cmd.OPCode == UdpConsts.OPCODE_LOGINACK)
{
if (cmd.Fields[0] == "OK")
{
Authed = true;
m_Parent.DebugDump("Authenticated with " + this.RemoteEP.ToString() + " OK. Connected!");
//Send the authenticated event to the third party application
m_Parent.AuthenticatedWithConnection(this, true, "");
}
else
{
m_Parent.DebugDump("Authentication to " + this.RemoteEP.ToString() + " Failed!");
//Send the not authed event
m_Parent.AuthenticatedWithConnection(this, false, cmd.Fields[1]);
//Disconnect the connection (but don't send a disconnection packet back)
m_Parent.RemoveConnection(this, false, cmd.Fields[1]);
}
return;
}
//Remote host disconnected from us
if (cmd.OPCode == UdpConsts.OPCODE_DISCONNECT)
{
m_Parent.RemoveConnection(this, false, cmd.Fields[0]);
return;
}
//Reliable packet acknowledgement
if (cmd.OPCode == UdpConsts.OPCODE_RELIABLEACK)
{
m_Parent.DebugDump("Received reliable ACK for packet " + cmd.Fields[0] + ".");
//Get the current reliable command
ReliableEntry rcmd = null;
RQueue.GetCurrentReliableCommand(out rcmd);
//If the sequence number from the one stored in the first field
//of the ACK is the same as the one in the queue, remove it.
if (rcmd != null)
{
try
{
if (rcmd.SequenceNum == Convert.ToUInt32(cmd.Fields[0]))
{
RQueue.NextReliableCommand();
ReliableEntry next_rel = null;
RQueue.GetCurrentReliableCommand(out next_rel);
if (next_rel != null)
{
m_Parent.DebugDump("Moving reliable packet queue - next packet is " + next_rel.SequenceNum.ToString());
//Send the next reliable packet
m_Parent.SendData(RemoteEP.Address.ToString(), RemoteEP.Port, next_rel.CommandPacket);
}
else
m_Parent.DebugDump("Moving reliable packet queue - no more packets on reliable queue.");
}
}
catch (Exception e)
{
m_Parent.DebugDump("Exception: " + e.Message);
}
}
}
//Give unrecognised commands to the application
if(Authed)
m_Parent.CommandReceived(this, cmd);
}
/// <summary>
/// Initialises the connection object, setting variables to defaults.
/// </summary>
/// <param name="udp">Reference to the main core engine that created the connection.</param>
public Connection(CommonUdp udp)
{
EncryptionKey = "";
RemoteEP = null;
LastSentPacket = 0;
LastReceivedPacket = 0;
LastSentPacketR = 1;
LastReceivedPacketR = 0;
LastReceivedPacketSeq = 0;
Authed = false; //Either (server) client is authed or (client) is authed with server
Server = false; //Connection is a server connection
m_Parent = udp;
TimeoutTime = DateTime.Now.AddSeconds(UdpConsts.CONNECTION_TIMEOUT);
CompoundCommand = null;
m_RequestID = "";
RQueue = new ReliableQueue();
}
/// <summary>
/// Called when a connection is attempting to authenticate
/// </summary>
/// <param name="cn">Connection</param>
/// <param name="cmd">Command</param>
/// <returns>UDP_OK or error code</returns>
internal int ConnectionAuthing(Connection cn, Command cmd)
{
//Is the connection already authed?
if(cn.Authed)
{
DebugDump("Connection " + cn.RemoteEP.ToString() + " sent an auth packet but is already authed? Command ignored.");
return UdpConsts.UDP_OK;
}
ConnectionAuthEventArgs ea = new ConnectionAuthEventArgs(cn, cmd);
DebugDump("Connection " + cn.RemoteEP.ToString() + " sent login data...");
//Have the third party client app process the login data
if (OnConnectionAuth != null)
OnConnectionAuth(null, ea);
//Clamp the disallow reason to 200 characters
if (ea.DisallowReason.Length > 200)
ea.DisallowReason = ea.DisallowReason.Substring(0, 200);
if (!ea.AllowConnection)
{
DebugDump("Login data is bad, rejecting connection.");
cn.SendUnreliableCommand(0, UdpConsts.OPCODE_LOGINACK, new string[] { "FAIL", ea.DisallowReason });
m_Clients.RemoveConnection(cn, true, ea.DisallowReason);
}
else
{
DebugDump("Login data is ok, connection authed.");
cn.SendUnreliableCommand(0, UdpConsts.OPCODE_LOGINACK, new string[] { "OK" });
cn.Authed = true;
}
return UdpConsts.UDP_OK;
}
/// <summary>
/// Called by a connection object when a command comes in
/// </summary>
/// <param name="cn">Connection that sent the command</param>
/// <param name="cmd">Command received</param>
/// <returns>UDP_OK or error code</returns>
internal int CommandReceived(Connection cn, Command cmd)
{
if (OnCommandReceived != null)
OnCommandReceived(null, new CommandEventArgs(cmd, cn, null));
return UdpConsts.UDP_OK;
}
/// <summary>
/// Processes a connectionless command.
/// </summary>
/// <param name="c">Command to process</param>
/// <returns>UDP_OK or error code.</returns>
private int ProcessConnectionlessComand(IPEndPoint remote_ep, Command c)
{
int retval = UdpConsts.UDP_OK;
try
{
//========================================================================
//Connection request from a remote host
if (c.OPCode == UdpConsts.OPCODE_CONNECTIONREQUEST)
{
Connection temp;
bool cant_connect = false;
m_Servers.ConnectionByIPPort(remote_ep.Address.ToString(), remote_ep.Port, out temp);
if (temp != null)
{
DebugDump("Unable to accept connection, connection exists in server list.");
retval = UdpConsts.UDP_ALREADYCONNECTED;
cant_connect = true;
}
m_Clients.ConnectionByIPPort(remote_ep.Address.ToString(), remote_ep.Port, out temp);
if (temp != null)
{
DebugDump("Unable to accept connection, connection exists in client list.");
retval = UdpConsts.UDP_ALREADYCONNECTED;
cant_connect = true;
}
//Can't accept this connection as we already have it in the list
//Client will just have to wait until it times out.
if (cant_connect)
{
SendConnectionlessCommand(remote_ep.Address.ToString(), remote_ep.Port, UdpConsts.OPCODE_CONNECTIONACK, new string[] { c.Fields[0], "FAIL", "Connection from this client already exists." });
return retval;
}
string encryption_key = "";
//Is encryption on? If so generate an encryption key.
if(m_bEncrypt)
encryption_key = Util.GenerateEncryptionKey();
//Create a new connection object and add it to the clients list...
Connection new_conn = new Connection(this);
new_conn.EncryptionKey = encryption_key;
new_conn.RemoteEP = remote_ep;
DebugDump("Remote host at " + remote_ep.ToString() + " requested a connection.");
DebugDump("Sending acknowledgement packet.");
SendConnectionlessCommand(remote_ep.Address.ToString(), remote_ep.Port, UdpConsts.OPCODE_CONNECTIONACK, new string[] { c.Fields[0], "OK", encryption_key });
DebugDump("Adding remote host to clients list.");
m_Clients.NewConnection(new_conn);
return UdpConsts.UDP_OK;
}
//========================================================================
//Connection acknowledge from a remote host
if (c.OPCode == UdpConsts.OPCODE_CONNECTIONACK)
{
DebugDump("Got connection acknowledgement from " + remote_ep.ToString() + ".");
if(!m_ConnTimeouts.EntryExists(c.Fields[0]))
{
//Make sure we actually _asked_ for this connection ack.
DebugDump("Connection accept packet sent by " + remote_ep.ToString() + " but was unrequested - ignored.");
}
else if (c.Fields[1] == "OK")
{
//Server accepted our connection.
DebugDump("Connection " + c.Fields[0] + " accepted by " + remote_ep.ToString());
//Create and store a connection object for the server that accepted us.
Connection new_con = new Connection(this);
new_con.EncryptionKey = c.Fields[2];
new_con.RemoteEP = remote_ep;
new_con.Server = true; //Is a connection to a server
new_con.RequestID = c.Fields[0];
m_Servers.NewConnection(new_con);
//Remove from the timeouts list
m_ConnTimeouts.RemoveConnectionEntry(c.Fields[0]);
//Sending login data is to be handled in the actual application
//Basically it needs to send an command packet to the host containing the login data.
DebugDump("Server is requesting login information, sending.");
if (OnLoginRequested != null)
OnLoginRequested(null, new LoginSendEventArgs(new_con, true, ""));
else
//Application did nothing, so send a blank login packet now.
SendCommand(remote_ep.Address.ToString(), remote_ep.Port, new_con.EncryptionKey, 0, 0, UdpConsts.OPCODE_LOGINDETAILS, null);
}
else
{
//Server did not accept our connection.
//Make a temporary connection object
Connection new_con = new Connection(this);
new_con.EncryptionKey = c.Fields[1];
new_con.RemoteEP = remote_ep;
new_con.Server = true; //Is a connection to a server
DebugDump("Connection not accepted - " + c.Fields[2] + ".");
if (OnLoginRequested != null)
OnLoginRequested(null, new LoginSendEventArgs(new_con, false, c.Fields[1]));
}
return UdpConsts.UDP_OK;
}
}
catch (Exception e)
{
DebugDump("Exception whilst processing connectionless command (" + e.Message + ")");
return UdpConsts.UDP_FAIL;
}
//========================================================================
//Call the event (so it can be handled in the application)
if (OnConnectionlessCommand != null)
OnConnectionlessCommand(null, new CommandEventArgs(c, null, remote_ep));
return UdpConsts.UDP_OK;
}
/// <summary>
/// Receive loop continually receives data.
/// </summary>
private void ReceiveLoop()
{
int iExCount = 0;
if(m_CurrentIP == "")
m_LocalEndPoint = new IPEndPoint(IPAddress.Any, m_CurrentPort);
else
m_LocalEndPoint = new IPEndPoint(IPAddress.Parse(m_CurrentIP), m_CurrentPort);
DebugDump("Created the local IP endpoint at " + m_LocalEndPoint.ToString( ));
try
{
m_Socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
DebugDump("Created the socket.");
m_Socket.Bind(m_LocalEndPoint);
DebugDump("Bound the socket to the local end point, now entering receive loop...");
m_iState = UdpConsts.UDP_STATE_LISTENING;
if (OnListenStateChanged != null)
OnListenStateChanged(null, new ListenEventArgs(true));
while (true)
{
try
{
//Make space to store the data from the socket
Byte[] received = new Byte[UdpConsts.MAX_COMMAND_LEN];
//Create an end point, just give it temporary values
EndPoint remoteEP = new IPEndPoint(m_LocalEndPoint.Address, m_LocalEndPoint.Port);
//Read bytes from the socket
int bytesReceived = m_Socket.ReceiveFrom(received, ref remoteEP);
IPEndPoint remoteIPEP = (IPEndPoint)remoteEP;
//string str_received = Encoding.UTF8.GetString(received);
string str_received = Util.BytesToString(received);
str_received = str_received.Substring(0, bytesReceived);
//Fire the received event if it is being used (allowing raw data to be caught)
if(OnDataReceived != null)
OnDataReceived(null, new ReceivedEventArgs((IPEndPoint)remoteEP, str_received));
//Handle connectionless packets
try
{
int pcmd = 0;
//Allocate a temporary command object
Command new_cmd = new Command();
//Parse the start of the command
new_cmd.OPCode = str_received.Substring(pcmd, 2);
pcmd += 2;
new_cmd.SequenceNum = Util.BytesToUint(str_received.Substring(pcmd, 4));
pcmd += 4;
new_cmd.Flags = (byte)str_received[pcmd];
pcmd++;
//If the command packet is connectionless then parse it now.
if ((new_cmd.Flags & UdpConsts.FLAGS_CONNECTIONLESS) > 0)
{
new_cmd.NumFields = Util.BytesToShort(str_received.Substring(pcmd, 2));
pcmd += 2;
new_cmd.FieldSizes = new short[new_cmd.NumFields];
for (short i = 0; i < new_cmd.NumFields; i++)
{
new_cmd.FieldSizes[i] = Util.BytesToShort(str_received.Substring(pcmd, 2));
pcmd += 2;
}
pcmd += 2;
new_cmd.AllFields = str_received.Substring(pcmd);
new_cmd.Initialize();
//Process the connectionless command
ProcessConnectionlessComand(remoteIPEP, new_cmd);
}
else
{
//Locate connection this command belongs to and process it there.
Connection conn;
//Check both the client and server lists
m_Clients.ConnectionByRemoteEndpoint(remoteIPEP, out conn);
if(conn == null)
m_Servers.ConnectionByRemoteEndpoint(remoteIPEP, out conn);
if (conn == null)
DebugDump("Connection-related packet with no matching connection arrived - ignored.");
else
conn.ProcessCommandPacket(str_received);
}
}
catch
{
DebugDump("Exception whilst parsing input from " + remoteIPEP.ToString() + " as command, probably not a command. Ignoring.");
}
//Reset the exception count to 0
iExCount = 0;
}
catch (SocketException se)
{
if ((se.ErrorCode != 10061) && (se.ErrorCode != 10054))
{
//Fire the socket error event.
if (se.ErrorCode != 10004)
{
if (OnSocketError != null)
OnSocketError(null, new SocketEventArgs(se.ErrorCode, se.Message));
}
DebugDump("Socket Exception in receive loop (" + se.ErrorCode.ToString() + "): " + se.Message);
if (m_iState != UdpConsts.UDP_STATE_LISTENING)
break;
iExCount++;
}
}
catch (Exception e)
{
DebugDump("Exception in receive loop: " + e.Message);
if (m_iState != UdpConsts.UDP_STATE_LISTENING)
break;
iExCount++;
}
if (iExCount == UdpConsts.MAX_EXCEPTIONS)
{
DebugDump("Got too many consecutive exceptions in the receive loop, terminating.");
break;
}
}
}
catch (SocketException se)
{
//Fire the socket error event.
if (OnSocketError != null)
OnSocketError(null, new SocketEventArgs(se.ErrorCode, se.Message));
DebugDump("Socket Exception (" + se.ErrorCode.ToString() + "): " + se.Message);
}
catch (Exception e)
{
DebugDump("Exception: " + e.Message);
}
//We are out of the loop but the server thinks we are not? make sure it does.
if((m_iState != UdpConsts.UDP_STATE_IDLE) && (m_iState != UdpConsts.UDP_STATE_CLOSING))
{
StopListen();
}
DebugDump("Set the system state to idle.");
//Set the state to idle.
m_iState = UdpConsts.UDP_STATE_IDLE;
DebugDump("Exited the receive loop.");
}
