60 lines
944 B
Go
60 lines
944 B
Go
|
package main
|
||
|
|
|
||
|
|
import (
|
||
|
|
"fmt"
|
||
|
|
"io"
|
||
|
|
"net"
|
||
|
|
)
|
||
|
|
|
||
|
|
type Server struct {
|
||
|
|
Frontends []*Frontend
|
||
|
|
}
|
||
|
|
|
||
|
|
type Frontend struct {
|
||
|
|
Server *Server
|
||
|
|
Backend Backend
|
||
|
|
}
|
||
|
|
|
||
|
|
func (fe *Frontend) Serve(ln net.Listener) error {
|
||
|
|
for {
|
||
|
|
conn, err := ln.Accept()
|
||
|
|
if err != nil {
|
||
|
|
return fmt.Errorf("failed to accept connection: %v", err)
|
||
|
|
}
|
||
|
|
|
||
|
|
// TODO: log errors to debug log
|
||
|
|
go fe.handle(conn)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
func (fe *Frontend) handle(downstream net.Conn) error {
|
||
|
|
defer downstream.Close()
|
||
|
|
|
||
|
|
be := &fe.Backend
|
||
|
|
upstream, err := net.Dial(be.Network, be.Address)
|
||
|
|
if err != nil {
|
||
|
|
return fmt.Errorf("failed to dial backend: %v", err)
|
||
|
|
}
|
||
|
|
defer upstream.Close()
|
||
|
|
|
||
|
|
return duplexCopy(upstream, downstream)
|
||
|
|
}
|
||
|
|
|
||
|
|
type Backend struct {
|
||
|
|
Network string
|
||
|
|
Address string
|
||
|
|
}
|
||
|
|
|
||
|
|
func duplexCopy(a, b io.ReadWriter) error {
|
||
|
|
done := make(chan error, 2)
|
||
|
|
go func() {
|
||
|
|
_, err := io.Copy(a, b)
|
||
|
|
done <- err
|
||
|
|
}()
|
||
|
|
go func() {
|
||
|
|
_, err := io.Copy(b, a)
|
||
|
|
done <- err
|
||
|
|
}()
|
||
|
|
return <-done
|
||
|
|
}
|