Big changes

This commit is contained in:
Yapollon 2025-02-20 23:18:43 +01:00
parent aeb8f642d6
commit 9ae2457416

210
main.go
View File

@ -2,6 +2,7 @@ package main
import (
"encoding/json"
"errors"
"fmt"
"net"
)
@ -12,6 +13,11 @@ const (
StatusResponseID = 0x00
)
const (
SEGMENT_BITS = 0x7F
CONTINUE_BIT = 0x80
)
type HandshakePacket struct {
ProtocolVersion int
ServerAddress string
@ -45,8 +51,13 @@ type Chat struct {
Text string `json:"text"`
}
type Reader struct {
data []byte
cursor int
}
func main() {
listener, err := net.Listen("tcp", ":25565")
listener, err := net.Listen("tcp", "localhost:25565")
if err != nil {
fmt.Println("Error starting server:", err)
return
@ -67,32 +78,52 @@ func main() {
}
func handleConnection(conn net.Conn) {
var packetID byte
if err := readByte(conn, &packetID); err != nil {
r := &Reader{data: make([]byte, 1024)}
// Print the whole packet
buf := make([]byte, 1024)
n, _ := conn.Read(buf)
r.data = buf[:n]
fmt.Println("Packet: ", r.data)
_, err := r.readVarInt()
if err != nil {
fmt.Println("Error reading first number:", err)
return
}
packetID, err := r.readVarInt()
if err != nil {
fmt.Println("Error reading packet ID:", err)
return
}
if packetID == HandshakePacketID {
handleHandshake(conn)
fmt.Println("Packet ID: ", packetID)
switch packetID {
case HandshakePacketID:
handleHandshake(r)
default:
fmt.Println("Unknown packet ID:", packetID)
}
}
func handleHandshake(conn net.Conn) {
func handleHandshake(r *Reader) {
var handshake HandshakePacket
if err := readHandshakePacket(conn, &handshake); err != nil {
if err := readHandshakePacket(r, &handshake); err != nil {
fmt.Println("Error reading handshake packet:", err)
return
}
if handshake.NextState == 1 {
handleStatusRequest(conn)
handleStatusRequest(r)
}
}
func handleStatusRequest(conn net.Conn) {
var packetID byte
if err := readByte(conn, &packetID); err != nil {
func handleStatusRequest(r *Reader) {
packetID, err := r.readVarInt()
if err != nil {
fmt.Println("Error reading packet ID:", err)
return
}
@ -119,46 +150,96 @@ func handleStatusRequest(conn net.Conn) {
return
}
if err := writeByte(conn, StatusResponseID); err != nil {
w := &Writer{data: make([]byte, 1024)}
if err := w.writeVarInt(StatusResponseID); err != nil {
fmt.Println("Error writing response ID:", err)
return
}
if err := writeVarInt(conn, len(response)); err != nil {
if err := w.writeVarInt(len(response)); err != nil {
fmt.Println("Error writing response length:", err)
return
}
if _, err := conn.Write(response); err != nil {
if err := w.writeString(string(response)); err != nil {
fmt.Println("Error writing response:", err)
return
}
}
}
func readByte(conn net.Conn, b *byte) error {
buf := make([]byte, 1)
_, err := conn.Read(buf)
if err != nil {
return err
func (r *Reader) readByte() (byte, error) {
if r.cursor >= len(r.data) {
return 0, errors.New("EOF")
}
*b = buf[0]
b := r.data[r.cursor]
r.cursor++
return b, nil
}
func (r *Reader) readVarInt() (int, error) {
value := 0
position := 0
for {
currentByte, err := r.readByte()
if err != nil {
return 0, err
}
value |= int(currentByte&SEGMENT_BITS) << position
if (currentByte & CONTINUE_BIT) == 0 {
break
}
position += 7
if position >= 32 {
return 0, errors.New("VarInt is too big")
}
}
return value, nil
}
func (r *Reader) readString() (string, error) {
length, err := r.readVarInt()
if err != nil {
return "", err
}
if r.cursor+length > len(r.data) {
return "", errors.New("EOF: Reached String unexpectedly")
}
str := string(r.data[r.cursor : r.cursor+length])
r.cursor += length
return str, nil
}
type Writer struct {
data []byte
cursor int
}
func (w *Writer) writeByte(b byte) error {
if w.cursor >= len(w.data) {
return errors.New("EOF")
}
w.data[w.cursor] = b
w.cursor++
return nil
}
func writeByte(conn net.Conn, b byte) error {
_, err := conn.Write([]byte{b})
return err
}
func writeVarInt(conn net.Conn, value int) error {
func (w *Writer) writeVarInt(value int) error {
for {
temp := byte(value & 0x7F)
temp := byte(value & SEGMENT_BITS)
value >>= 7
if value != 0 {
temp |= 0x80
temp |= CONTINUE_BIT
}
if _, err := conn.Write([]byte{temp}); err != nil {
if err := w.writeByte(temp); err != nil {
return err
}
if value == 0 {
@ -168,27 +249,72 @@ func writeVarInt(conn net.Conn, value int) error {
return nil
}
func readVarInt(conn net.Conn, value *int) error {
var result int
var shift uint
func (w *Writer) writeString(s string) error {
length := len(s)
if err := w.writeVarInt(length); err != nil {
return err
}
if w.cursor+length > len(w.data) {
return errors.New("EOF")
}
copy(w.data[w.cursor:], s)
w.cursor += length
return nil
}
func writeByte(conn net.Conn, b byte) error {
_, err := conn.Write([]byte{b})
return err
}
func writeVarInt(conn net.Conn, value int) error {
var buf [5]byte
n := 0
for {
var b byte
if err := readByte(conn, &b); err != nil {
return err
temp := byte(value & SEGMENT_BITS)
value >>= 7
if value != 0 {
temp |= CONTINUE_BIT
}
result |= int(b&0x7F) << shift
shift += 7
if b&0x80 == 0 {
buf[n] = temp
n++
if value == 0 {
break
}
}
*value = result
return nil
_, err := conn.Write(buf[:n])
return err
}
func readHandshakePacket(conn net.Conn, packet *HandshakePacket) error {
if err := readVarInt(conn, &packet.ProtocolVersion); err != nil {
func readHandshakePacket(r *Reader, packet *HandshakePacket) error {
// Print the whole packet
fmt.Println("Packet: ", r.data)
fmt.Println("Works so far")
var err error
packet.ProtocolVersion, err = r.readVarInt()
fmt.Println("version: ", packet.ProtocolVersion)
if err != nil {
return err
}
packet.ServerAddress, err = r.readString()
fmt.Println(packet.ServerAddress)
if err != nil {
return err
}
port, err := r.readByte()
if err != nil {
return err
}
packet.ServerPort = uint16(port)
packet.NextState, err = r.readVarInt()
fmt.Println("Next state: ", packet.NextState)
if err != nil {
return err
}
return nil
}