70行代码实现tcp一对多转发

公司接入了联通的sgip协议通道，回执状态的鉴权放在了云主机，公司有三网ip各一个，要求在某一个网络出现故障时，回执能够从其他ip回来，不影响业务，运维找第三方实现软件无果，问题提交到我这里。

无他，唯祭出golang大法！

import (
	"flag"
	"fmt"
	"io"
	"math/rand"
	"net"
	"strings"
	"time"
)
var internalServers []string
func main() {
	var (
		port  = flag.String("port", ":1234", "Port")
		hosts = flag.String("hosts", "", "Hosts")
	)
	flag.Parse()
	internalServers = strings.Split(*hosts, ",")
	listener, err := net.Listen("tcp", *port)
	if err != nil {
		fmt.Println("Error listening:", err)
		return
	}
	defer listener.Close()
	fmt.Println("Listening on port ", *port)
	for {
		conn, err := listener.Accept()
		if err != nil {
			fmt.Println("Error accepting connection:", err)
			continue
		}
		go handleConnection(conn)
	}
}

func handleConnection(conn net.Conn) {
	defer conn.Close()
	// 将连接转发到内部服务器
	forwardToInternalServer(conn)
}

func forwardToInternalServer(conn net.Conn) {
	//internalServers := []string{"127.0.0.1:8081", "127.0.0.1:8082"}
	server := internalServers[randInt(len(internalServers))]
	fmt.Printf("Forwarding to %s\n", server)
	// 建立与内部服务器的连接
	internalConn, err := net.Dial("tcp", server)
	if err != nil {
		fmt.Println("Failed to connect to internal server:", err)
		return
	}
	defer internalConn.Close()
	// 使用io.Copy双向转发数据
	go copyData(conn, internalConn)
	go copyData(internalConn, conn)
}

func copyData(src, dst net.Conn) {
	_, err := io.Copy(dst, src)
	if err != nil {
		fmt.Println("Error copying data:", err)
	}
	src.Close()
	dst.Close()
}

func randInt(n int) int {
	rand.Seed(time.Now().UnixNano())
	return rand.Intn(n)
}

直接编译：go build -o tcp转发.exe

在云主机上运行：tcp转发.exe -port :7890 -hosts aaa.xxx.xxx.xx:2222,bbb.xxx.xxx.xx:2222

搞定!golang大法好！