/// <summary>
/// Adds a new connection to the list
/// </summary>
/// <param name="conn">Connection to add</param>
/// <returns>UDP_OK or error code</returns>
public int NewConnection(Connection conn)
{
if (conn == null)
{
return(UdpConsts.UDP_FAIL);
}
m_Parent.DebugDump("Adding connection entry for " + conn.RemoteEP.ToString() + ".");
lock (List.SyncRoot)
{
List.Add(conn);
}
//Send the event
m_Parent.ConnectionStateChanged(conn, true, "");
return(UdpConsts.UDP_OK);
}
/// <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.");
}
}
