Network protocol

The network protocol of Ace of Spades is rather simple (even though it hasn't been fully documented yet).

Overview

The protocol uses UDP. Pretty much all variables are big-endian (apart from a few), and every datagram packet consists of:

• A 2-byte header, consisting of flags (compressed, has timer), an unique value, and the connection id.
• A 2-byte timer (if the timer flag is set)
• Packets data (this is compressed if the compressed flag is set)

The compression is probably dynamic Huffman (see pyspades for a decompression routine).

Every packet consists of

• 1-byte packet ID (and a flag that's set if an ACK is wanted)
• 1-byte sequence type (0 and 0xFF - basically,
• 2-byte sequence number (used for ACK)
• Packet-specific data

There are 11 different packet types:

• 1 -> ACK
• 2 -> Connection request
• 3 -> Connection response
• 4 -> Disconnect
• 5 -> Ping
• 6 -> Sized data (includes chat messages, sending name, position data, etc.)
• 7 -> Sized unknown (not used?)
• 8 -> Sized map data (sent in chunks)
• 9 -> Unreliable sized data with additional sequence (for orientation)
• 10 -> Unknown (used)
• 11 -> Unknown (not used?)

For the sized data types, there are different packet types for master/server/client. For further reading, see pyspades.

pyspades

pyspades is a project that attempts to document the protocol and write an alternative server in Python.

It can be found at http://code.google.com/p/pyspades/

The information above was taken from this project. Findings and contributions should be made to pyspades for a better understanding of the protocol.