Module wire 

Minecraft Java Edition framing for the Server List Ping and the front of login: VarInt length-prefixed packets, the handshake, status JSON, ping/pong, Login Start, the login Disconnect, and the pre-1.7 legacy ping (0xFE) with its 0xFF kick reply.

Shared by the server and the client. Every length the peer announces is checked against a bound before anything is allocated for it.

Structs

Handshake

LegacyPing

What a legacy (0xFE) ping carried.

Reader

A cursor over one packet’s body.

Constants

DEFAULT_PROTOCOL

DEFAULT_VERSION_NAME

The version reported when the handler names none: 1.21.1.

IO_TIMEOUT

Deadline for each read and write, as the vanilla server’s read timeout.

LEGACY_PING_PROTOCOL

Protocol a 1.6 legacy ping carries.

LEGACY_TAIL_WAIT

How long the legacy ping’s optional tail (01, then FA + MC|PingHost) is waited for.

MAX_ADDRESS_CHARS

Handshake server address, in characters.

MAX_CLIENTBOUND_PACKET

Largest packet the client accepts: a status response is one String of at most 32767 chars.

MAX_JSON_CHARS

A Java String field holds at most 32767 UTF-16 units; the status JSON and a disconnect reason are both bounded by it.

MAX_LEGACY_PAYLOAD

Bytes of a 1.6 MC|PingHost payload accepted.

MAX_SAMPLE

Players listed in a status sample.

MAX_SERVERBOUND_PACKET

Largest packet a client may send the server (handshake, Login Start, ping are all tiny).

MAX_USERNAME_CHARS

Login Start player name, in characters.

STATE_LOGIN

STATE_STATUS

STATE_TRANSFER

Functions

decode_legacy_reply

Decode a 0xFF kick reply (after the 0xFF and the u16 length) into status fields.

disconnect_json

A login Disconnect reason as the JSON text component the client renders.

encode_handshake

encode_legacy_ping

The 1.6 client’s legacy ping: FE 01 FA + MC|PingHost naming host:port.

encode_legacy_reply

The 0xFF kick packet answering a legacy ping. 1.4+ clients get §1\0protocol\0version\0motd\0online\0max; a bare 0xFE gets motd§online§max, where § is the separator and is therefore removed from the MOTD.

encode_login_start

Login Start as a client of protocol sends it.

format_uuid

frame

A complete packet (length prefix included) from an id and body.

get_varint

Decode a VarInt from the front of buf: (value, bytes used).

parse_handshake

parse_login_start

Login Start: the name, and the UUID when the version’s layout carries one. The layout changed four times; the trailing bytes are read by shape rather than by version number.

parse_uuid

plain_text

Flatten a chat component (a string, an object with text/translate/extra, or an array) to plain text. Nesting beyond 32 levels is cut off rather than followed.

put_string

put_varint

read_legacy_ping

Read the rest of a legacy ping after its 0xFE: the optional 0x01, then the optional 1.6 0xFA MC|PingHost plugin message. Each tail is waited for briefly, as the vanilla server does, because older clients send nothing more.

read_packet

Read one uncompressed packet’s id and body. None on a clean EOF between packets.

read_raw

Read one packet’s bytes after its length prefix; the announced length is checked against max before any of it is read. None on a clean EOF between packets.

split_id

Split an uncompressed packet into its id and body.

status_json

The status JSON for a minecraft_status action; client_protocol is unused unless the handler asks to echo it (protocol: "echo").