Go Traffic Forwarding Implementation

In Golang, implementing traffic forwarding functionality is typically done using TCP or UDP features within the net package. Here is a simple example code that demonstrates a basic TCP traffic forwarding functionality:

package main

import (
    "fmt"
    "net"
    "os"
)

func main() {
    // 监听端口
    ln, err := net.Listen("tcp", "localhost:8080")
    if err != nil {
        fmt.Println("Error listening:", err)
        os.Exit(1)
    }
    defer ln.Close()

    fmt.Println("Listening on localhost:8080")

    // 接受客户端连接
    for {
        conn, err := ln.Accept()
        if err != nil {
            fmt.Println("Error accepting connection:", err)
            os.Exit(1)
        }
        fmt.Println("Accepted connection from", conn.RemoteAddr())

        // 将数据转发到目标地址
        go func(conn net.Conn) {
            targetAddr := "localhost:9090"
            targetConn, err := net.Dial("tcp", targetAddr)
            if err != nil {
                fmt.Println("Error connecting to target:", err)
                conn.Close()
                return
            }
            defer targetConn.Close()

            // 进行数据转发
            go func() {
                _, err := io.Copy(targetConn, conn)
                if err != nil {
                    fmt.Println("Error copying data to target:", err)
                }
            }()

            _, err = io.Copy(conn, targetConn)
            if err != nil {
                fmt.Println("Error copying data to client:", err)
            }

            conn.Close()
        }(conn)
    }
}

In the above code, we start by listening on port 8080 on localhost and accepting client connections. Whenever a new client connects, we create a new goroutine to handle the connection, forwarding the client’s data to the target address localhost:9090 and also sending the target address’s data back to the client. Finally, we close the connection.

Of course, this is just a simple example, in real-world applications, one may need to consider more error handling, as well as optimization and security considerations.