Simple connection fowarder in golang
Just a quicky. I love the simplicity how you can solve issues in golang.
I was trying to port forward something but had to have it on a public IP.
ssh did not do what I want so I just wrote a quick and dirty version in golang:
package main
import (
"io"
"log"
"net"
"os"
)
func forward(conn net.Conn) {
client, err := net.Dial("tcp", os.Args[2])
if err != nil {
log.Fatalf("Dial failed: %v", err)
}
log.Printf("Connected to localhost %v\n", conn)
go func() {
defer client.Close()
defer conn.Close()
io.Copy(client, conn)
}()
go func() {
defer client.Close()
defer conn.Close()
io.Copy(conn, client)
}()
}
func main() {
if len(os.Args) != 3 {
log.Fatalf("Usage %s listen:port forward:port\n", os.Args[0]);
return
}
listener, err := net.Listen("tcp", os.Args[1])
if err != nil {
log.Fatalf("Failed to setup listener: %v", err)
}
for {
conn, err := listener.Accept()
if err != nil {
log.Fatalf("ERROR: failed to accept listener: %v", err)
}
log.Printf("Accepted connection %v\n", conn)
go forward(conn)
}
}