Version byte

[jdonszelmann]

We have a couple of options for the first byte in the ipv8 packet.

Right now the header looks like
0x00 0x02 where as far as we know 0x02 is the version and the first byte is hardcoded to 0.

There are a few logical options for a new header:

• Option 1: extend the scheme
  • 0x00 0x03 for rust-ipv8 messages
• Option 2: reduce the byte count. start the message with
  • 0x01and everything after will be new rust-ipv8 messages with slightly different architecture.
• Option 3:
  • Use a proper magic byte like 0b00101010.

Advantages of this kind of proper magic byte is that few other protocols use it so it is very easily detectable. If this is actually an advantage is debatable.

We should decide upon this soon as this it is rather important to distinguish the two kinds of messages. By then legacy py-ipv8 messages will be interpreted by rust and converted to a rust-readable standard.

[ichorid]

The proper way to do this is to use 4 magic bytes at the beginning. One byte is not enough to uniquely distinguish the protocol for, say, Wireshark analysis. Also, a single byte is a little bit less efficient in parsing than 4 bytes because of alignment issues. It is always a good idea to put longer-aligned scalar fields first.

Please, look into best practices on this.

[NULLx76]

We (@jonay2000, @dsluijk and I) think that 0x20f57c03 is a good candidate for the magic byte. It is as far as we know unique. The trailing 03 signifies the version of the protocol.

[dsluijk]

Transferring, as this is more about the protocol definition

[jdonszelmann]

sources for choices made to get to the number: https://tools.ietf.org/html/draft-main-magic-00