/
main.go
79 lines (66 loc) · 1.33 KB
/
main.go
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/* multiple port version of port forwarding */
package main
import (
"fmt"
"io"
"log"
"net"
)
func main() {
conns := make(chan net.Conn)
for port := 5000; port < 6000; port++ {
listen(uint(port), conns)
}
for conn := range conns {
log.Println("new client connected to", conn.RemoteAddr(), conn.LocalAddr())
go handleRequest(conn)
}
}
func listen(port uint, ch chan net.Conn) {
ln, err := net.Listen("tcp", fmt.Sprintf(":%d", port))
if err != nil {
log.Printf("Error listening at port %d\n%v", port, err)
return
}
log.Printf("listen at %d", port)
go func() {
for {
conn, err := ln.Accept()
if err != nil {
log.Printf("Error accepting at port %v\n%v", port, err)
return
}
ch <- conn
}
}()
}
func handleRequest(conn net.Conn) {
fmt.Println("served at port", conn.LocalAddr())
handlers := getHandlers()
for _, handler := range handlers {
handler.Do(conn)
}
}
func getHandlers() []Handler {
var h Upstream
return []Handler{&h}
}
type Handler interface {
Do(conn net.Conn)
}
type Upstream struct {
}
func (uh *Upstream) Do(conn net.Conn) {
const upstream = "127.0.0.1:80"
proxy, err := net.Dial("tcp", upstream)
if err != nil {
panic(err)
}
go copyIO(conn, proxy)
go copyIO(proxy, conn)
}
func copyIO(src, dest net.Conn) {
defer src.Close()
defer dest.Close()
io.Copy(src, dest)
}