init commit

.gitignore

@@ -0,0 +1,2 @@
+config.json
+/gateway

cmd/gateway/main.go

@@ -0,0 +1,140 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net"
+	"os"
+	"sync"
+)
+
+type Config struct {
+	Port    int               `json:"port"`
+	Hosts   map[string]string `json:"hosts"`
+	Default string            `json:"default"`
+}
+
+var config Config
+
+func loadConfig() error {
+	file, err := os.Open("config.json")
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	byteValue, err := io.ReadAll(file)
+	if err != nil {
+		return err
+	}
+
+	return json.Unmarshal(byteValue, &config)
+}
+
+func main() {
+	if err := loadConfig(); err != nil {
+		panic(err)
+	}
+
+	// 监听TCP端口
+	listener, err := net.Listen("tcp", fmt.Sprintf(":%d", config.Port))
+	if err != nil {
+		panic(err)
+	}
+	defer listener.Close()
+	fmt.Println("Listening on :25565")
+
+	for {
+		// 接受传入的连接
+		conn, err := listener.Accept()
+		if err != nil {
+			fmt.Println("Error accepting:", err.Error())
+			continue
+		}
+		// 处理连接
+		go handleRequest(conn)
+	}
+}
+
+func handleRequest(conn net.Conn) {
+	// 确保连接关闭
+	defer conn.Close()
+
+	buf := make([]byte, 1024)
+	n, err := conn.Read(buf)
+	if err != nil {
+		fmt.Println("Error reading:", err.Error())
+		return
+	}
+	mc_host := GetMcHost(buf[:n])
+	host, ok := config.Hosts[mc_host]
+	if !ok {
+		host = config.Default
+	}
+
+	client, err := net.Dial("tcp", host)
+	if err != nil {
+		fmt.Println("Error dialing:", err.Error())
+		return
+	}
+	defer client.Close()
+
+	client.Write(buf[:n])
+
+	var wg sync.WaitGroup
+	wg.Add(2)
+
+	go handleRead(client, conn, &wg)
+	go handleWrite(client, conn, &wg)
+
+	wg.Wait()
+}
+
+func handleRead(srv, cli net.Conn, wg *sync.WaitGroup) {
+	defer func() {
+		wg.Done()
+		srv.Close()
+		cli.Close()
+	}()
+
+	buf := make([]byte, 1024)
+
+	for {
+		n, err := srv.Read(buf)
+		if err != nil {
+			return
+		}
+
+		cli.Write(buf[:n])
+	}
+}
+
+func handleWrite(srv, cli net.Conn, wg *sync.WaitGroup) {
+	defer func() {
+		wg.Done()
+		srv.Close()
+		cli.Close()
+	}()
+
+	buf := make([]byte, 1024)
+
+	for {
+		n, err := cli.Read(buf)
+		if err != nil {
+			return
+		}
+
+		srv.Write(buf[:n])
+	}
+}
+
+func GetMcHost(buf []byte) string {
+	buf = buf[4:]
+	host_len := buf[0]
+	if len(buf)+1 < int(host_len) {
+		return ""
+	}
+
+	return string(buf[1 : host_len+1])
+}

config.example.json

@@ -0,0 +1,8 @@
+{
+    "port": 25565,
+    "default": "mc1:25565",
+    "hosts": {
+        "dev": "mc1:25565",
+        "dev.lan": "mc1:25568"
+    }
+}

go.mod

@@ -0,0 +1,3 @@
+module github.com/tursom/mc-gateway
+
+go 1.23.1