redirect network stream

redcon.go

package main

import (
	"log"
	"io"
	"os"
	"crypto/tls"
	"strings"
	"net"
	"flag"
	"time"
)

func redCon(r io.ReadCloser,w io.Writer) {
	defer r.Close()
	buf := make([]byte,100)
	for {
		nr,err := r.Read(buf)
		if err == os.EOF {break}
		if err != nil {log.Println("Read:",err);break}
		w.Write(buf[:nr])
	}
}

func redirect(sock net.Listener,mkCon func() (net.Conn,os.Error)) {
	for {
		conn, err := sock.Accept()
		if err != nil {
			log.Fatal(err)
		}
		red_to,err := mkCon()
		if err != nil {log.Println("Error connecting",err);continue}
		go redCon(conn, red_to)
		go redCon(red_to, conn)
	}
}

func mkTls(addr string) func() (net.Conn,os.Error) {
	if !strings.Contains(addr,":") {
		addr += ":443"
	}
	return func() (net.Conn,os.Error) {
		return tls.Dial("tcp",addr,nil)
	}
}

func mkTcp(addr string) func() (net.Conn,os.Error) {
	if !strings.Contains(addr,":") {
		addr += ":80"
	}
	return func() (net.Conn,os.Error) {
		return net.Dial("tcp",addr)
	}
}

var SERVER_CERT = []byte(`-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----`)
var SERVER_KEY  = []byte(`-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----`)

func mkSSLListener(addr string) (l net.Listener, err os.Error) {
	config := &tls.Config{
		//Rand: rand.Reader,
		Time: time.Nanoseconds,
	}
	config.Certificates = make([]tls.Certificate, 1)
	config.Certificates[0], err = tls.X509KeyPair(SERVER_CERT,
		SERVER_KEY)
	if err != nil {
		log.Printf("Certificates: ", err.String())
		return
	}
	l, e := tls.Listen("tcp", addr, config)
	if e != nil {
		log.Printf("Listen error : ", e)
		return
	}
	return
}

func mkTCPListener(addr string) (l net.Listener,err os.Error) {
	tcpaddr, err := net.ResolveTCPAddr("tcp", addr)
	if err != nil {log.Fatal("Resolve:",err)}
	l,err = net.ListenTCP("tcp", tcpaddr)
	return
}


func main() {
	var dialWithTls bool
	var listenWithTls bool
	var listenPort string
	flag.StringVar(&listenPort, "l", ":8080", "Address we'll listen to")
	flag.BoolVar(&dialWithTls, "rtls", false, "connect to target with SSL")
	flag.BoolVar(&listenWithTls, "ltls", false, "Listen to connections with SSL")
	flag.Parse()
	if flag.NArg() == 0 {log.Fatal("No address to connect")}
	lmap := map[bool]func(string)(net.Listener,os.Error){true:mkSSLListener,false:mkTCPListener}
	lsn, err := lmap[listenWithTls](listenPort)
	if err != nil {log.Fatal("Listen:",err)}
	maker := mkTcp(flag.Arg(0))
	if dialWithTls {
		log.Println("Dialing with TLS")
		maker = mkTls(flag.Arg(0))
	}
	redirect(lsn,maker)
}