GO语言实现TCP端口转发

package main

import (
        "fmt"
        "log"
        "net"
)

func main() {
        //源端口，目的端口
        var fromport, toport int = 2222, 88
        fromaddr := fmt.Sprintf("127.0.0.1:%d", fromport)
        toaddr := fmt.Sprintf("127.0.0.1:%d", toport)

        fromlistener, err := net.Listen("tcp", fromaddr)

        if err != nil {
                log.Fatal("Unable to listen on: %s, error: %s\n", fromaddr, err.Error())
        }
        defer fromlistener.Close()

        for {
                fromcon, err := fromlistener.Accept()
                if err != nil {
                        fmt.Printf("Unable to accept a request, error: %s\n", err.Error())
                } else {
                        fmt.Println("new connect:" + fromcon.RemoteAddr().String())
                }

                //这边最好也做个协程，防止阻塞
                toCon, err := net.Dial("tcp", toaddr)
                if err != nil {
                        fmt.Printf("can not connect to %s\n", toaddr)
                        continue
                }

                go handleConnection(fromcon, toCon)
                go handleConnection(toCon, fromcon)

        }

}

func handleConnection(r, w net.Conn) {
        defer r.Close()
        defer w.Close()

        var buffer = make([]byte, 100000)
        for {
                n, err := r.Read(buffer)
                if err != nil {
                        break
                }

                n, err = w.Write(buffer[:n])
                if err != nil {
                        break
                }
        }

}

参考链接：GO语言实现TCP端口转发【代码】_苏南生的CSDN博客-CSDN博客