Filter workaround for mBot arrow purchase problem

[sarkoplata]

Hey guys,
So as you know the new servers are mostly all only ch. In these servers mbot cannot purchase arrow from Hotan Blacksmith. The reason is simple: mBot tries to buy arrows from the 5th tab. (acutally 6th tab becuase it is 0-indexed) Because on an original Hotan Blacksmith, there is also an EU Option at the Blacksmith:



However if you edit your server to be CH Only, the EU option will be gone(everyone does this) and hence the arrow will be at 2nd tab (actually 3th tab because it is 0-indexed). But mbot will still try to buy it from the 5th tab. That's why it won't be able to get arrows.

There's a quick, dirty workaround I found about this, and tried it on a server and it works fine. This is not a execute-a-query/download-an-exe kind of fix, you have to add this piece of codes to your filter source.

So mbot goes to same coordinate to buy arrows. First we must make sure we detect it's going to be a arrow purchase so we don't fuck up any other purchase.

Declare a public bool, I called mine "InterfereNextArrowPurchase".
(I know im not parsing the coordinate correctly but who cares)

 Spoiler

if (_pck.Opcode == 0x7021) // client_movement
                                {
                                    this.InterfereNextArrowPurchase = false;
                                    
                                    byte NormalWalk = _pck.ReadUInt8();

                                    if (NormalWalk == 1)
                                    {
                                        ushort X = _pck.ReadUInt16();
                                        ushort Y = _pck.ReadUInt16();
                                        ushort Z = _pck.ReadUInt16();
                                        ushort Q = _pck.ReadUInt16();

                                        if (X == 23687)
                                        {
                                            if (Y == 510)
                                            {
                                                if (Z == 0 && Q == 740)
                                                {
                                                    this.InterfereNextArrowPurchase = true;
                                                }
                                            }
                                        }
                                    }
                                }

If the character is moving to that exact coordinate, we know it will probably be an arrow purchase by mbot.
We reset our variable everytime a move packet is sent.

Now let's interfere that purhcase packet.

 Spoiler

if (_pck.Opcode == 0x7034) //inventory movement_ clientsided
                                {
                                    byte typex = _pck.ReadUInt8();

                                    if (typex == 8 && this.InterfereNextArrowPurchase)
                                    {
                                        byte tab = _pck.ReadUInt8();
                                        byte idk = _pck.ReadUInt8();
                                        UInt16 amt = _pck.ReadUInt16();
                                        UInt32 id = _pck.ReadUInt32();

                                        if (tab == 5)
                                        {
                                            Packet mbotfix = new Packet(0x7034);
                                            mbotfix.WriteUInt8(8);
                                            mbotfix.WriteUInt8(2);
                                            mbotfix.WriteUInt8(idk);
                                            mbotfix.WriteUInt16(amt);
                                            mbotfix.WriteUInt32(id);
                                            SendPacketToServer(mbotfix);

                                            continue;
                                        }

                                    }

                                }

So we got the client side done. This will be enough mbot to buy arrows correctly. However, the client still thinks it sends a buy packet for tab 5, however the result will come as 2. This will crash the client. That's why we also edit the 0xB034 result packet.

 Spoiler

if (p.Opcode == 0xB034) // SERVER_INVENTORY_MOVEMENT
                                {
                                    if (this.IsBot && this.InterfereNextArrowPurchase)
                                    {
                                        byte success = p.ReadUInt8();
                                        if (success == 1)
                                        {
                                            byte type = p.ReadUInt8();
                                            if (type == 8)
                                            {
                                                byte tab = p.ReadUInt8(); // 2 to 5
                                                byte idk1 = p.ReadUInt8();
                                                byte idk2 = p.ReadUInt8();
                                                byte idk3 = p.ReadUInt8();

                                                ushort amt = p.ReadUInt16();
                                                UInt32 idk4 = p.ReadUInt32();

                                                Packet mbotfixer = new Packet(0xB034);
                                                mbotfixer.WriteUInt8(1);
                                                mbotfixer.WriteUInt8(8);
                                                mbotfixer.WriteUInt8(5);
                                                mbotfixer.WriteUInt8(idk1);
                                                mbotfixer.WriteUInt8(idk2);
                                                mbotfixer.WriteUInt8(idk3);
                                                mbotfixer.WriteUInt16(amt);
                                                mbotfixer.WriteUInt32(idk4);
                                                SendPacketToClient(mbotfixer);
                                                continue;
                                            }
                                        }
                                    }
                                }

And that's it. mBot can purchase arrows from hotan blacksmith with no problems now

[qoaway]

isnt that easy just remove from client side shopping data and leave the server shopping tables

[sarkoplata]

Originally Posted by qoaway

isnt that easy just remove from client side shopping data and leave the server shopping tables

doesn't work and even if it did 0xb034 would crash your client.

[qoaway]

Originally Posted by sarkoplata

doesn't work and even if it did 0xb034 would crash your client.

than instead of "detecting" bot and arrow buying; correct the B034 packet. Still easier and less complex

[sarkoplata]

Originally Posted by qoaway

than instead of "detecting" bot and arrow buying; correct the B034 packet. Still easier and less complex

Bot detection is just an extra precaution I have for myself, since I already have to detect it for some other stuff. This is still an easy fix, idc about making it less complex - this way I don't have to touch to database.

Lots of servers are telling their players to go buy arrows from Donwhang, they can't fix this. This may help them.