Simple tcp proxy to a single origin address

tcpproxy.go

package main

import (
	"log"
	"net"
	"os"

	"github.com/getlantern/netx"
)

func main() {
	addr := os.Args[1]
	log.Printf("will forward to %s", addr)

	l, err := net.Listen("tcp", ":8080")
	if err != nil {
		log.Fatal(err)
	}
	log.Printf("listening at %s", l.Addr())

	for {
		in, err := l.Accept()
		if err != nil {
			log.Printf("unable to accept connection: %v", err)
			continue
		}
		go func() {
			defer in.Close()
			log.Printf("dialing %s", addr)
			out, err := net.Dial("tcp", addr)
			if err != nil {
				log.Printf("unable to connect to %s: %v", addr, err)
				return
			}
			defer out.Close()
			inErr, outErr := netx.BidiCopy(out, in, make([]byte, 50), make([]byte, 50))
			log.Printf("inErr: %v\n", inErr)
			log.Printf("outErr: %v\n", outErr)
		}()
	}
}