Archive/brook/protocol/brook-wsserver-wbp-protocol.md

brook wsserver --withoutBrookProtocol protocol

Terminology

• DST Address: The address that the application actually wants to request, address contains IP/domain and port

  ATYP + IP/Domain + PORT
  

  • ATYP: 1 byte
    • 0x01: IPv4
    • 0x03: Domain
    • 0x04: IPv6
  • IP/Domain: 4/n/16 bytes
    • If ATYP is 0x01, then this is IPv4, 4 bytes
    • If ATYP is 0x03, then this is domain, n bytes, and the first byte is the domain length
    • If ATYP is 0x04, then this is IPv6, 16 bytes
  • Port: 2 bytes
    • Big Endian 16-bit unsigned integer

• Password: User-defined password

• SHA256: Defined in FIPS 180-4

Client --TCP--> Server

[Standard WebSocket Protocol Header] + [SHA256(Password) + (DST Address Length+4) + Unix Timestamp + DST Address] + [DATA]...

The maximum length of [SHA256(Password) + (DST Address Length+4) + Unix Timestamp + DST Address] is 2048 bytes

• DST Address Length+4: Big Endian 16-bit unsigned integer
• Unix Timestamp: If it is not even, it should be increased by 1. Big Endian 32-bit unsigned integer
• DATA: Actual data being proxied

Server --TCP--> Client

[Standard WebSocket Protocol Header] + [DATA]...

Client --UDP(UDP over TCP)--> Server

[Standard WebSocket Protocol Header] + [SHA256(Password) + (DST Address Length+4) + Unix Timestamp + DST Address] + [Fragment Length + Fragment]...

The maximum length of [SHA256(Password) + (DST Address Length+4) + Unix Timestamp + DST Address] is 2048 bytes
The maximum length of [Fragment Length + Fragment] is 65507 bytes

• DST Address Length+4: Big Endian 16-bit unsigned integer
• Fragment Length: Big Endian 16-bit unsigned integer
• Fragment: Actual data being proxied
• Unix Timestamp: If it is not odd, it should be increased by 1. Big Endian 32-bit unsigned integer

Server --UDP(UDP over TCP)--> Client

[Standard WebSocket Protocol Header] + [Fragment Length + Fragment]...

The maximum length of [Fragment Length + Fragment] is 65507 bytes

• Fragment Length: Big Endian 16-bit unsigned integer
• Fragment: Actual data being proxied