[Bug] TCP relay is incorrect

nange commented 1 year ago

Verify steps

[X] Is this something you can debug and fix? Send a pull request! Bug fixes and documentation fixes are welcome.
[X] I have searched on the issue tracker for a related issue.

Version

latest

What OS are you seeing the problem on?

Linux

Description

We should exec TCPConn.CloseWrite() instead of SetReadDeadline when io.CopyBuffer() completed.

CLI or Config

tun2socks --device tun://tun0 --proxy direct:// -interface wlp0s20f3

Logs

No response

How to Reproduce

The source of client:

package main

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

func main() {
    if len(os.Args) <= 1 {
        fmt.Println("please enter some greeting message")
        return
    }

    conn, err := net.Dial("tcp", "your-ip:port")
    if err != nil {
        fmt.Println("dial:", err.Error())
        return
    }
    defer conn.Close()

    if _, err := conn.Write([]byte(os.Args[1])); err != nil {
        fmt.Println("write greeting message to remote:", err.Error())
        return
    }

    if err := conn.(*net.TCPConn).CloseWrite(); err != nil {
        fmt.Println("close write:", err.Error())
        return
    }

    ret := make([]byte, 1024)
    nr, err := conn.Read(ret)
    if err != nil {
        fmt.Println("read from remote:", err.Error())
        if nr > 0 {
            fmt.Println("read from remote:", string(ret[:nr]))
        }
        return
    }
    fmt.Println("read from remote:", string(ret[:nr]))
}

The source of remote:

package main

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

func main() {
    if len(os.Args) <= 1 {
        fmt.Println("please set server port using os.Args[1]")
        return
    }
    lis, err := net.Listen("tcp", ":"+os.Args[1])
    if err != nil {
        fmt.Println("listen:", err.Error())
        return
    }
    fmt.Println("server listen on :" + os.Args[1])
    for {
        conn, err := lis.Accept()
        if err != nil {
            fmt.Println("accept:", err.Error())
            continue
        }
        go handleConn(conn)
    }
}

func handleConn(conn net.Conn) {
    defer conn.Close()

    for {
        b := make([]byte, 1024)
        nr, err := conn.Read(b)
        if err != nil {
            fmt.Println("read:", err.Error())
            if nr > 0 {
                fmt.Println("read err, bug got:", b[:nr])
            }
            return
        }
        fmt.Println("read:", string(b[:nr]))
        time.Sleep(10 * time.Second)
        if _, err := conn.Write(b[:nr]); err != nil {
            fmt.Println("write to remote:", err.Error())
        }
    }
}

Steps

Compile client and remote source code
Run remote bin on remote server
Run tun2socks on local server
Set proper ip route on local server
Run client bin on local server. (eg: ./test hello)

What did you expect to see?

On local server:

read from remote: hello

What did you see instead?

read from remote: EOF